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How has social media affected the mental health and self-esteem of adolescents?

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How has social media affected the mental health and self-esteem of adolescents?

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KEY POINTS

Evidence from a variety of cross-sectional, longitudinal and empirical studies implicate smartphone and social media use in the increase in mental distress, self-injurious behaviour and suicidality among youth; there is a dose-response relationship, and the effects appear to be greatest among girls.

Social media can affect adolescents' self-view and interpersonal relationships through social comparison and negative interactions, including cyberbullying; moreover, social media content often involves normalization and even promotion of self-harm and suicidality among youth.

High proportions of youth engage in heavy smartphone use and media multitasking, with resultant chronic sleep deprivation, and negative effects on cognitive control, academic performance and socioemotional functioning.

Clinicians can work collaboratively with youth and their families, using open, nonjudgmental and developmentally appropriate approaches to reduce potential harms from social media and smartphone use, including education and practical problem-solving.

There is a need for public awareness campaigns and social policy initiatives that promote nurturing home and school environments that foster resilience as youth navigate the challenges of adolescence in today's world.

In the last decade, increasing mental distress and treatment for mental health conditions among youth in North America has paralleled a steep rise in the use of smartphones and social media by children and adolescents.

In Ontario, the proportion of teenagers reporting moderate to serious mental distress increased from 24% in 2013, to 34% in 2015 and to 39% in 2017, 1 with parallel increases in health service utilization. Inpatient hospital admissions of children and adolescents for mental health reasons increased substantially across Canada between 2007 and 2014, while admissions for other medical conditions in this age group decreased by 14%. 2 Between 2009 and 2014, admissions to hospital for intentional self-harm increased by 110% in Canadian girls. 3 Suicide is now the second leading cause of death for Canadian youth. 4 A recent analysis of survey data found the 12-month prevalence of suicidal ideation, attempts and nonsuicidal self-injury to be 8.1%, 4.3% and 8.8%, respectively, among adolescents aged 14 to 17 years, with all rates being higher in girls. 5 Similarly, administrative data in the United States show that presentations to hospital for suicidal ideation or attempts among children and adolescents almost doubled between 2008 and 2015, with the highest increase for adolescent girls. 6 Self-poisoning rates among 10- to 18-year-olds, which had declined in the US since the turn of the century, increased substantially from 2011 to 2018, primarily among girls. 7 Surveys of high school students in the US have shown a similar pattern for self-reported symptoms of depression, major depressive episodes and suicidality over the last 2 decades. 8,9

At the same time, social media use has increased markedly. In the US, the proportion of young people between the ages of 13 and 17 years who have a smartphone has reached 89%, more than doubling over a 6-year period; moreover, 70% of teenagers use social media multiple times per day, up from a third of teens in 2012. 10 The percentage of Ontario's teenagers who reported spending 5 or more hours a day on social media increased from 11% in 2013, to 16% in 2015 and to 20% in 2017. 1 An analysis of Australian longitudinal data found that 86% of students owned smartphones in grade 8, increasing to 93% by grade 11, with increased use of social media communication with age. 11

We review the evidence that links smartphone and social media use with mental distress and suicidality among adolescents. We do not review evidence for online gaming. Although most existing data are observational, making causality difficult to establish, findings from a few longitudinal, randomized and controlled studies suggest that social media and smartphone use may be contributing to the rising burden of mental distress among youth. We consider the clinical implications of existing evidence, to help practising clinicians to work collaboratively with youth and families to mitigate potential negative effects of social media and smartphone use on mental health.

How has use of social media been shown to affect adolescents' sense of self?

Two cross-sectional surveys of American and German university students, respectively, 12,13 found that students who spent more time on the social media platform Facebook were more likely to endorse feeling envy or sensing that others in their social network were better off than they were. The term "FOMO" - fear of missing out - has been defined as "a pervasive apprehension that others might be having rewarding experiences from which one is absent," 14 and has been associated with increased stress related to Facebook use. 15

A systematic review of 20 studies found that use of social media was associated with body image concerns and disordered eating. 16 In a randomized study, female participants reported more negative mood after just 10 minutes of browsing their Facebook account compared with those who browsed an appearance-neutral control website. 17 Moreover, participants who were high in appearance comparison tendency reported an increased desire to change the appearance of their face, hair or skin after spending time on Facebook, in comparison with those who browsed the control website. 17

The nature of social media interactions, which are arm's length, makes negative commenting both easy and more frequent than in-person interactions with peers. An Ontario survey of middle- and high school students showed that the odds of suicidal ideation, plans and attempts were all significantly higher among those who had experienced cyberbullying, even after controlling for a range of potential confounders. 18

Does social media addiction exist and can it affect mental health?

One study of repeat survey data from 2013, 2014 and 2015 associated the extent of self-reported use of Facebook with subsequent poor self-reported mental health and life satisfaction. 19 Concerns have been raised about social media platforms having been deliberately designed - in highly sophisticated ways that use behavioural psychology, neuroscience and artificial intelligence - to promote behavioural reinforcement and behavioural addiction. 20,21 Several cross-sectional studies have shown that high proportions of youth appear to be addicted to their smartphones, 22,23 but there is no standard or agreed-upon definition of smartphone or Internet addiction; studies have used different definitions and scales, varying from those that rely on behavioural addiction criteria, to measurement of the extent of functional impairment and level of device use. 24,25 As such, reported prevalence rates are highly variable. 25

A systematic review identified Internet addiction as being particularly associated with self-harm or suicidal behaviour based on 7 included studies, all of which were cross-sectional school-based surveys that used validated outcome measures and were rated as high or medium to high quality. 24 A recent large prospective study of senior high school adolescent students in Taiwan found that youth classified as experiencing Internet addiction had a significantly increased risk of having newly emerged self-harm or suicidal behaviour or both when re-evaluated 1 year later. 26

Two systematic reviews have shown that media multitasking is associated with negative effects on cognitive control, academic performance and socioemotional functioning in youth. 27,28 Most existing studies, however, are cross-sectional, and measures are heterogenous across studies with limited attempts to consider individual and contextual differences, making it impossible to establish causality. Youth with lower impulse control may be more susceptible to deleterious effects of media multitasking. A large longitudinal study of adolescents who did not have significant symptoms of attention-deficit/hyperactivity disorder (ADHD) at baseline found that high-frequency digital media use was positively associated with emergence of symptoms meeting Diagnostic and Statistical Manual of Mental Disorders-4th Edition (DSM-IV) criteria for ADHD over a 2-year follow-up period, even after adjusting for known confounders. 29

Can social media promote self-harm?

Youth communicate thoughts of suicidality and self-harm behaviours online, including sharing images of self-inflicted injuries. Explicit depiction of self-injury - particularly cutting - on social media is common, as shown by site content studies 30,31 that found photographs or live videos of self-injurious behaviour, many of which had no warnings about graphic content. Of particular concern were viewers' comments, which typically contained positive feedback or personal disclosures about self-injury experiences, and rarely offered encouragement or discussion of recovery. Such findings show the potential for mental illness romanticizing and messaging that normalizes self-harm among youth. Indeed, a systematic review that included 26 studies (using qualitative, descriptive or cross-sectional methodology) found that social media platforms included normalization of self-harm behaviour, discussions about practical issues regarding suicidality and live depictions of self-harm acts. 32 At the same time, there were also positive elements, including providing a sense of community, suggestions for seeking treatment and advice on stopping self-harm behaviour.

Do the effects of smartphones on social skills affect mental health?

An observational study showed that spending more than a few hours per week using electronic media correlated negatively with self-reported happiness, life satisfaction and self-esteem, whereas time spent on nonscreen activities (in-person social interactions, sports or exercise, print media, homework, religious services, working at a paid job) correlated positively with psychological well-being, among adolescents. 33 Other observational studies have linked spending more than 2 hours a day on social networking sites and personal electronic devices with high rates of suicidality and depressive symptoms among adolescent girls, although youth who sustained high levels of face-to-face socializing were relatively protected against the negative consequences of too much time online. 13,34

Youth do increasingly interact online rather than in person, and smartphones can interfere even with face-to-face interactions via what has been termed "phubbing": attending to one's phone when in the presence of others. 35 A recent empirical field study using experience sampling in 304 participants showed that even the mere presence of phones on a table caused participants who were randomly assigned to that condition to feel more distracted and have lower enjoyment during social interactions compared with those who were randomized to putting their phone away. 36 Phone use was also found to predict distraction, which in turn predicted greater boredom and worse overall mood. 36

Does sleep-loss associated with use of social media affect mental health?

An analysis of US annual survey data found an abrupt increase in the proportion of adolescents getting insufficient sleep after 2011-2013, with more than 40% sleeping less than 7 hours most nights in 2015. 37 The study also showed an exposure-response relationship between daily electronic media use beyond 2 or more hours per day, and insufficient sleep. 37 An analysis of survey data from Ontario found that 63.6% of 5242 students aged 11-20 years slept less than recommended, 38 also showing a significant relationship between use of social media beyond 1 hour a day and odds of insufficient duration of sleep. 38

In a 14-day, randomized, crossover experimental study under well-controlled conditions, use of electronic screens before bedtime was shown to disrupt sleep in multiple ways: longer time to fall asleep and decreased evening sleepiness, reduced melatonin secretion, circadian clock delay, reduced amount and delay in rapid eye movement sleep, and reduced next-morning alertness. 39 A systematic review and meta-analysis that included 20 studies on the association between portable screen-based media devices and sleep outcomes found that use of media at bedtime was associated with decreased duration and quality of sleep and excessive daytime sleepiness. 40 Of note, the mere presence of portable screen-based media devices in the bedroom was shown to disrupt sleep, 40 possibly related to the temptation to check media devices when they are present or owing to a conditioned response involving increased arousal.

Data from a longitudinal study of 1101 adolescents in Australia showed that poor sleep mediated the relationship between nighttime mobile phone use and subsequent depressed mood, externalizing behaviours and decline in self-esteem and coping based on various validated scales. 11 In another longitudinal study involving 2286 adolescents in Europe, magnitude of Internet use in general had a negative impact on mental health, but the most robust effects came from the consequences - in particular, lack of sleep from Internet use had a notable adverse effect on mental health on 4-month follow-up based on measures from a validated depression, anxiety and stress scale. 41

Are some individuals more susceptible to mental health effects than others?

Although population-based studies suggest a link between social media use and mental distress among youth, the impact of these technologies may vary among individuals - and some may be less susceptible to harm, as indicated by an emerging literature of experimental studies. Girls and young women tend to spend more time on social media than boys do, have more exposure to cyberbullying and show tendency to experience more mental health effects, 10,34 which is consistent with recent epidemiologic trends indicating that depressive symptoms, self-harm and suicidality have increased among young females in particular. 5⁻9

The context of social media use may mediate its effects. A structural equation modelling analysis of a cross-sectional survey of 910 high school students in Belgium found that, among girls, passive use of Facebook had a negative impact on mood but active use had a positive impact on perceived online social support, which in turn had a positive impact on mood. 42 However, for boys active site use had a negative effect. A systematic review of 70 studies found that while social media use was correlated with depression, anxiety and measures of well-being, effects could be both detrimental (such as from negative interactions and social comparison) and beneficial (such as through social connectedness and support) depending on the quality of interactions and individual factors. 43 Certain cognitive styles, such as those that involve rumination and brooding, appeared to exacerbate negative effects of social media. 43 Moreover, the negative impact of social media on depressive symptoms appears to be much greater for adolescents with low levels of in-person interaction; in contrast, youth with high levels of face-to-face socializing appear to be relatively protected against the negative consequences of too much time online. 34 A recent survey of 1124 college students found that while social media contact in the absence of a face-to-face relationship was associated with depressive symptoms, the proportion of social media contacts with whom participants had a close face-to-face relationship was negatively associated with depressive symptoms. 44 In addition, the challenges associated with social media may be especially risky for young people who are already experiencing mental health difficulties, as suggested by the bidirectional relationship between use of electronic media and decrease in psychological well-being. 33 Of particular concern for such vulnerable individuals is that educational or even promotional content about suicide and self-harm is readily available and widely accessed online. 30,31

The role of individual differences in terms of the effects of social media is a topic of active investigation. Recent experimental studies have shown relationships between individual characteristics and social media experiences. In a randomized study of 120 college students, those who scored highly on the tendency to engage in social comparison based on measures from a validated scale had poorer self-perceptions, lower self-esteem and more negative affect after browsing the Facebook profile of an acquaintance, relative to those randomized to the control conditions, an effect not seen among students who scored low on social comparison traits. 45 In another empirical study, 102 college students who were asked to take a selfie were randomized to either of 3 conditions with different numbers of "likes" (average, above average and below average); those rated as having a greater sense of purpose in life based on measures from a validated scale had lower sensitivity to feedback (based on number of "likes") on their self-photograph posts. 46 A study that categorized participants by social comparison orientations ("ability-based" versus "opinion-based") found that different orientations showed different emotional responses to being compared with others, which in turn was related to life satisfaction. 47 These early findings offer some insights for the individualized care of youth presenting with emotional and mental distress.

How might physicians use this evidence to inform their practice?

Despite the limitations of the evidence base at this time, clinicians may be able to use currently available knowledge in their practice, combined with evidence on effecting behavioural change in youth.

Clinicians treating youth with mental illness and those at risk of mental distress can discuss with adolescents and their families the known risks of social media and smartphone use to mental health. Clinicians may choose to advocate for a harm reduction approach, suggesting reduced use of social media and the Internet rather than abstinence for youth, given evidence that suggests prolonged use is associated with poorer mental health. A recent large systematic review found that communication with adolescents is most effective in the context of a therapeutic alliance that is open and nonjudgmental, elicits trust and emotional safety, and offers a sense of inclusion and autonomy. 48

Encouraging parents to be proactively involved in limiting children's and teens' use of smartphones and social media may be helpful, given that social media use appears to become problematic when it surpasses 1 to 2 hours daily. 34,38 Results from a recent meta-analysis suggest that while parental limits may be effective at reducing the amount of media use by younger children, open discussion focused on positive engagement and guidance might be best for reducing media-related risks for adolescents; however, only 5 of the 52 included studies pertained to social media, all of which were based on cross-sectional surveys. 49 It is also worth reminding parents that they model smartphone use with their own behaviour; a randomized study showed that heavy parental smartphone use was associated with poorer quality of interactions with their children. 50 Youth and their families can be encouraged to set boundaries for smartphone and social media use. These could include such measures as using social media only for set times, and preferably only in common living areas in the home. A further motivator may be to discuss evidence showing an adverse impact of smartphones on learning, 51 and the benefit on academic outcomes when phones are put away when studying, preferably in another room. 52

A qualitative study that collected data via focus groups with adolescent girls found that high levels of confidence, high media literacy and sound appreciation of individual differences appeared to mitigate negative effects of social media on body image. 53 The participants reported that "these characteristics were nurtured by positive parental influence and a supportive school environment." 53 These findings underscore the importance of a nurturing home and school environment in fostering resilience as youth navigate the challenges of adolescence. An empirical study of the effect of Instagram browsing on affect in just more than 500 adolescents found that randomization to conditions that provided greater contextual awareness regarding posts by others mitigated against postbrowsing negative affect in teens who reported higher levels of negative social comparison. 54

Sleep hygiene measures specific to social media and smartphone usage are crucial, as several studies have shown that increased smartphone use can disrupt sleep and shorten sleep duration. These would include avoiding use of electronic screens within 1 to 2 hours before bedtime, and not having portable, screen-based media devices in bedrooms overnight.

The American Academy of Pediatrics provides a number of useful health and safety tips to support youth regarding the use of social media, 55 as well as a Family Media Use Plan that offers structure to the recommendations related to limiting use and having discussions regarding appropriate use. 56 Further, the American Academy of Pediatrics has partnered with Common Sense Media to produce a Family Media Toolkit that has useful information for parents. 57 Other practical strategies to mitigate negative effects from using smartphones and related media are offered by the Center for Humane Technology ( http://humanetech.com/), an organization developed by former technology industry members out of concern for the potential deleterious effects of new media on psychological states.

A motivational interviewing approach may be useful to help young people start to make changes in their pattern of online behaviour. Motivational interviewing is an intervention with established effectiveness for adolescents with substance use, which could be useful for youth who appear to have poor self-control in their use of social media or smartphone. 58 This approach should involve open, nonjudgmental exploration of all aspects of a youth's digital life, including positive and negative. Some youth might benefit from habit reversal training to address compulsive use, including having daily "nonscreen time" that can be progressively increased. Sharing evidence that a randomized controlled trial found that participants assigned to not using Facebook reported significantly greater "life satisfaction" and positive emotions after 1 week, compared with controls who were told to continue using the site as usual, 59 may be helpful in effecting change. Youth might be encouraged to inform their friends that they are taking a break from, or otherwise limiting, their social media use. Talking with youth about alternative ways to connect, including meeting in person or even talking directly by phone, could help with strategies to fill the social media gap, reinforced by discussion of evidence that in-person interaction may protect mental health.

At the system level, school and community-based programs can institute limits on social media and smartphone use, along the lines of those that have recently been shown to have a positive effect on healthy behaviours. 60 However, such interventions should be developmentally appropriate and aim to respectfully ensure adolescents' autonomy. 61 Mobile-phone policies at the school and classroom level have been implemented in several jurisdictions, with mixed results. 62 Enforcement of blanket bans is often a challenge; rather, a more productive approach involves negotiation between teacher and students, as developmentally appropriate, in the context of a relationship built on mutual trust and respect for autonomy. 63,64

More broadly, public awareness campaigns can provide education on the impact of problematic use of digital media and promote healthy behaviours in this regard. Various social media platforms have placed bans and restrictions on content related to self-harm. 24 A qualitative study of focus groups involving a total of 66 adolescents found that while adolescents valued freedom and privacy, they recognized a need for protection and most were in favour of automatic monitoring in situations that were beyond their control. 65 Finally, there should be public discussion about the extent to which social media companies can use features that are deliberately designed to promote behavioural reinforcement and addiction, 20,21 particularly on platforms used primarily by youth.

Encouragingly, youth are increasingly recognizing the negative impact of social media on their lives and starting to take steps to mitigate this. 66 According to a recent poll, 54% of teens felt they spend too much time on their cell phone, and about half reported cutting back on the time they spend on it. 67

Conclusion

Given the importance of engaging youth in mitigating potential harms from social media, a prohibitionist approach would be counterproductive. The American Academy of Pediatrics suggests that online relationships are part of typical adolescent development. 55 Indeed, for adolescents today, who have not known a world without social media, digital interactions are the norm, and the potential benefits of online access to productive mental health information - including media literacy, creativity, self-expression, sense of belonging and civic engagement - as well as low barriers to resources such as crisis lines and Internet-based talking therapies cannot be discounted.

However, today's youth could benefit from proven individual and systemic interventions to help them navigate the challenges brought about by use of smartphones and social media, protect themselves from harm and use social media in a manner that safeguards their mental health, against a background of policy initiatives aimed at addressing the social, environmental and economic factors that underpin family well-being and nurture youth resilience. 68

Acknowledgements

The authors acknowledge the valuable contributions of the anonymous reviewers and journal editors.

Footnotes

CMAJ Podcasts: author interview at https://soundcloud.com/cmajpodcasts/190434-ana

Competing interests: None declared.

This article has been peer reviewed.

Contributors: All of the authors contributed to the conception and design of the work. Elia Abi-Jaoude and Karline Treurnicht Naylor drafted the manuscript. All authors revised the manuscript critically for important intellectual content, gave final approval of the version to be published and agreed to be accountable for all aspects of the work.

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Smartphones, social media use and youth mental health

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KEY POINTS In the last decade, increasing mental distress and treatment for mental health conditions among youth in North America has paralleled a steep rise in the use of smartphones and social media by children and adolescents. In Ontario, the proportion of teenagers reporting moderate to serious

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Economic development & Enviornmental Protection

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How can countries balance the need for economic development with the preservation of natural resources?

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How can countries balance the need for economic development with the preservation of natural resources?

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With growing populations, how do humans plan for food scarcity?

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With growing populations, how do humans plan for food scarcity?

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The food sustainability challenge

Food and its environmental impacts

For many policy makers, climate change is the major environmental problem we face, and here the food system's contribution is considerable. Estimates find that the food system as a whole contributes between 15 and 28 % to overall GHG emissions in developed countries, with all stages in the supply chain, from agricultural production through processing, distribution, retailing, home food preparation and waste, playing a part⁽⁾. Agricultural production makes the single largest contribution to overall impacts, accounting for nearly half of food-related GHG emissions in developed countries and more (in relative terms) in developing regions where post-harvest supply chains are less developed. While the direct impacts of farming (from CH ₄ and N ₂O emissions) contribute around 10-12 % of global emissions⁽Reference Smith, Martino, Cai, Metz, Davidson, Bosch, Dave and Meyer ³⁾, there are also indirect impacts to consider. Agriculturally induced deforestation causes the release of CO ₂ into the atmosphere, and taking this into account adds a further 6-17 % to agriculture's share of the burden. Once all direct and indirect impacts are summed, agriculture's contribution to the global emissions total has been estimated to account for as much as 30 %⁽Reference Bellarby, Foereid and Hastings ⁴⁾ ( Fig. 1).

In addition to CO ₂ release, agriculturally induced deforestation is the main cause of biodiversity loss worldwide. It is also responsible for 70-80 % of all human water withdrawals (water scarcity is becoming more widespread in many parts of the world) and is a significant cause of water pollution⁽Reference Jägerskog and Jønch Clausen ⁵⁾. The use of fertilisers, manure and N-fixing legumes have disrupted global N and P cycles, with negative impacts on water quality, aquatic ecosystems and marine fisheries⁽Reference Foley, Ramankutty and Brauman ⁶⁾.

Not all foods make an equal contribution to these linked problems of climate, biodiversity loss, resource depletion and pollution. Numerous assessments of individual food products find that meat and dairy products carry a disproportionately high environmental burden, with GHG emissions a particular concern⁽Reference Williams, Audsley and Sandars ⁷⁻Reference Westhoek, Rood and van den Berg ¹⁰⁾. Global estimates suggest that livestock production accounts for about 12-18 % of global GHG emissions⁽,⁾ and about half of the food system's total impacts, more when land use change impacts are included⁽Reference Audsley, Brander and Chatterton ¹³⁾. Since consumption of these foods is high in developed nations, growing rapidly in industrialising, and starting to increase among urban consumers in low income countries, their contribution is set to rise.

Livestock farming is responsible for other environmental impacts too. The sector uses 70 % of agricultural land overall and a third of arable land, and as such plays a leading role in CO ₂ release and biodiversity loss from deforestation. For example, cattle ranching and soya production (grown for animal feed) are the key drivers of deforestation in the fragile Amazon region⁽Reference McAlpine, Etter and Fearnside ¹⁴,Reference Nepstad, Soares-Filho and Merry ¹⁵⁾. Livestock are also the largest source of water pollution in the agricultural sector and a major user of finite irrigation water; much of the anticipated increase in irrigation water in coming years will be attributable to increasing production of animal feed to meet rising demand for livestock products⁽,⁾.

The impacts of livestock farming, and agriculture in general, are a consequence of the way farming is practised both in the developed and the developing worlds. They reflect both the problems associated with wealth and excess; and of poverty and insufficiency. Thus the high-input-high output industrial agriculture found in the wealthier countries has enabled and fostered excessive use of environmentally damaging non-renewable inputs and has made possible diets high in resource- and GHG-intensive foods such as meat and dairy products. At the same time, the farming practices of the world's poorest peoples are characterised by insufficiency: by a lack of agricultural inputs, irrigation water and land. This 'malnourishment' of the land gives rise to soil degradation, while attempts to compensate for low yields may trigger further land clearance; or, where additional land is not available, population pressures on existing land.

The nutrition food security challenge

The environmental problems caused both by excess and insufficiency are played out in the nutritional arena too. Globally about 35 % of adults are overweight, with half a billion of them obese⁽⁾. Obesity is affecting people at ever younger ages: today 43 million preschool children or nearly 7 % of all under fives, are overweight⁽⁾. Obesity and its attendant health consequences are, moreover, no longer only rich world problems. The majority of overweight and obese people today are citizens of low and middle income countries, largely living in urban areas, and many of them are poor. Thus while a quarter of deaths in developed countries are attributable to diet and physical inactivity-related risks, they are linked to 18 % of deaths low- and middle-income countries; many more people in absolute terms⁽⁾.

The causes of obesity are multifaceted⁽⁾, but energy rich diets combined with sedentary lifestyles are major risk factors. Today's agricultural system has increased access for many to energy- and fat-dense foods; these include not just high sugar processed foods and vegetable oils but also, critically, GHG-intensive meat and dairy products⁽Reference Popkin and Gordon-Larsen ²¹⁻Reference Zhai, Wang and Du ²³⁾. It is worth noting the link between vegetable oils and livestock farming: oilseeds are grown both for their oil fraction and for the oilseed cake that is used as animal feed. The synergistic relationship between these two production patterns may help increase availability of both, so ratcheting up consumption.

Coexistent with ill health caused by excess consumption, about 850 million people are undernourished; their diets lack sufficient energy⁽Reference Swinburn, Sacks and Hall ²⁴,⁾. A total of 3·5 million children under five die each year from under nutrition⁽Reference Black, Allen and Bhutta ²⁶⁾. An even greater proportion of people worldwide, including many who are overweight, have diets that are imbalanced, and lack the right mix of essential nutrients for healthy development, such as vitamin A, folate, Fe and Ca. For example, approximately one-third of the world's preschool-age population is estimated to be vitamin A deficient; up to 50 % in Africa and South-East Asia. Ca deficiency is the main cause of rickets in many parts of the world. An estimated 35-80 % of children in countries such as Turkey, India, Egypt, China, Libya and Lebanon are vitamin D deficient. Anaemia, much of it Fe-deficiency related, affects about 25 % of the global population, including 47 % of preschool children and one in two pregnant women, with the prevalence much higher in Africa⁽,⁻⁾.

Addressing the food sustainability challenge: three perspectives

What can be done to address the problem of food system sustainability? The solutions proposed very much depend upon how the problem is conceptualised, and broadly speaking three main 'takes' or perspectives, on the issues and their interactions, appear to be emerging. One perspective places emphasis on the negative consequences of food production; through this framing, there is a need to address these impacts by developing farming and post-harvest supply chain approaches that cause less damage. A second highlights the consumption patterns that drive production of high-impact foods, such as meat and dairy products; the way forward is therefore to seek to try and alter these. And a third picks out the problem of inequality, the coexistence of excess with insufficiency, that characterises both the environmental damage caused by production and the health problems linked to consumption, arguing for a more equitable food system.

To summarise, depending on one's view point, the problem can be conceptualised as a production challenge, in which case there is a need to change how food is produced by improving the unit efficiency of food production, termed here the 'production efficiency' perspective; a consumption challenge, which requires changes to the dietary drivers that determine food production (and may also include a focus on population growth) and 'demand restraint'; or a socio-economic challenge, which requires changes in how the food system is governed i.e. 'food system transformation.'

Many observers recognise that the problem requires a multifaceted approach and it would be simplistic to divide them into separate camps. However, there are certainly differences of emphasis: stakeholders tend to feel more comfortable with one framing of the problem over the other, and argue for action accordingly. These different emphases in turn reflect divergent beliefs about the role of technology and the potential it holds to address the problems we face; the extent to which it is possible to alter human behaviours; and the malleability of global institutions and the global economy. More fundamentally, however, which frame stakeholders choose to privilege will reflect their different visions of what sustainability actually 'looks' like, based on deeper ethical and aesthetic convictions in relation to our role in the natural world, the nature of human progress, definitions of freedom and ultimately what constitutes the 'good life'.

The section that follows describes these different perspectives, investigates the implications for nutrition and explores some of the underpinning values driving these three approaches.

The production challenge: improve efficiency

The challenge is conceptualised as follows: the human population is growing and urbanising; we are increasingly becoming net consumers and a dwindling proportion of the world's people will be engaged in farming in coming years, at least as their main activity. As incomes rise, people's food preferences are changing, with demand for meat and dairy foods on the rise. To meet this demand, food production may need to rise by as much as 60-110 % by 2050 overall⁽⁻⁾. At the same time, environmental damage caused by food production (both direct impacts and those related to deforestation) needs to be reduced.

More food must therefore be produced to feed urban consumers on existing farmland in ways that do not incur excessive environmental costs. Technological innovations and managerial changes are seen as key to reducing environmental impacts and increasing supply. For agriculture, the main strategies include: measures to improve efficiency such as the precise matching of inputs (fertilisers, water and pesticides) to outputs (plant or livestock requirements); technologies to recover energy from agricultural 'waste' (such as anaerobic digestion); and farming practices that sequester carbon in soils⁽,Reference Shafer, Walthall and Franzluebbers ³⁴⁾. Post harvest, emissions can be reduced through the development of refrigeration, manufacturing and transport technologies that are more energy efficient or based on renewable energy sources. Waste is minimised through better inventory management, by modifying packaging and portion sizes and through other approaches that either prolong the shelf life of foods or help consumers reduce food waste in other ways⁽⁾.

This perspective currently dominates the discourse on food sustainability. Its 'more for less' agenda constitutes the main, albeit not the only, focus of concern for governments⁽⁾ and for food industry actors such as agricultural input businesses, farming unions, manufacturers and retailers⁽,⁾. Demand projections are based on assumptions about income growth and its relationship with demand for certain foods, particularly meat⁽⁾ and there is little expectation that such demand could be significantly influenced or moderated. For some, moves towards moderation may pose a threat, given the economic importance of livestock and their nutritional value⁽,⁾.

While the other dimensions of food security (access, utilisation and stability over time)⁽⁾ and the quality of food are also recognised as important, in practice relatively less attention is paid to these other concerns.

As regards the nutritional quality of what is being produced: the task of agriculture is to supply the commodities that the market demands, based on the laws of supply and demand that in turn reflect individual consumer choices. Nutritional objectives can be met through other means, retrospectively as it were. For example, just as environmental efficiencies can be achieved through more optimised farming practices, so 'health efficiencies' can be secured through product reformulations that deliver foods similar in taste to the originals but lower in fat, sugar or salt, or with enhanced nutrition (prebiotics, n-3 fatty acids). Portion resizing can also reduce energy intakes per unit. Supported by appropriate information such as labelling, the consumer is then free to choose the healthier option without fundamentally needing to change their diet⁽⁻⁾. Physical activity is also promoted as a way to address the demand side of the energy balance, while pharmaceutical approaches may also be considered⁽Reference Caveny, Caveney and Somaratne ⁴⁵,Reference Halpern, Oliveira and Faria ⁴⁶⁾.

The high GHG intensity of meat and dairy products, and their association through complex health pathways with various negative health outcomes are recognised (although importantly the health benefits of animal products are also emphasised). However, both environmental and health concerns, from this perspective, can be addressed through technological means. Breeding, feeding and housing strategies, together with research into ways of inhibiting methane emissions from ruminant livestock, can reduce the per unit environmental footprint of meat and dairy production⁽Reference Shafer, Walthall and Franzluebbers ³⁴,⁾. The corollary, nutritional approach is to provide consumers with meat that is leaner and dairy products that are lower in fat (through animal breeding and feeding strategies, or by removing the fat after production) and to encourage people to choose these foods over higher fat options. Such an approach offers the promise of providing consumers with essential micronutrients (Fe, Ca, Zn and so forth) without the 'downsides' of fat and energy⁽⁻Reference Wyness, Weichselbaum and O'Connor ⁵⁰⁾.

In low income contexts, increased production of all foods can help address the problem of hunger caused by energy deficiencies and the need to produce 'more food' is sometimes considered as a moral imperative by farming interests. The importance of meat and dairy foods to consumers in low income countries, where diets are often grain based and lacking in diversity, is underlined. In addition to increased livestock production, post harvest food fortification and supplementation as well as biofortification (breeding crops higher in target nutrients) offer routes to addressing micronutrient deficiencies, with the food industry playing a key role⁽,⁾. Biofortification is considered particularly promising: while initial research investment costs are high, ex ante assessments suggest their cost effectiveness in addressing deficiencies is even greater⁽Reference Meenakshi, Johnson and Manyong ⁵³⁾.

To summarise: this is a globalised, 'macro' vision of a food system, and, of all the three perspectives, is the one most in keeping with current economic and political trends. It addresses the food security-environmental challenge primarily as an urban-oriented supply side problem. Market signals suggest that people want Western-style food that is convenient to prepare, often processed and reliant on sophisticated supply chains, and that includes substantial quantities of animal products. Since this is the 'problem', the solution is to deliver what people apparently want in ways that have lower negative impacts.

This perspective also sees a key role for the food industry in providing foods that meet current preferences at less 'cost' to health or that even positively enhance health, both in the developed and developing world. Fortification, biofortification, supplementation and an increase in low cost livestock production will improve the nutrient density of the foods available, while obesity can be addressed through product reformulations, information, and medical interventions where appropriate. Less attention is paid to the concept of dietary diversity, except in so far as increases in meat production will, for some, increase the range of foods consumed.

Consumers are rational beings who can make decisions based on the weighting of different preferences. Their choices should not be proscribed; consumption patterns should not be influenced by 'nanny statist' regulations and such like. While efforts are made to improve the environmental and health profile of foods through the approaches outlined earlier, consumer choice in relation to these foods i.e. how much of them they eat, is not a subject for consideration.

There a strong strand of optimism underlying this approach: it presents a positive vision of human ingenuity and of our ability to develop technological solutions to our problems. There is also a strong belief in freedom and individual agency, defined as the primacy of consumer choice, manifested through the workings of the market. Freedom is the freedom to consume, to attain a better life defined in terms of increased material possessions and more of the foods currently consumed in the developed world.

However, the efficiency vision may also be upheld by those with a less democratic orientation. Powerful interest groups may support this perspective because it reinforces existing power structures. Others may support the efficiency approach because they are essentially pessimistic about human nature: human subjects are incapable of restraining their desires and current socio-political inequities are entrenched and immutable. All that can be done is to shave away at the problem through technological improvements.

The consumption challenge: demand restraint

In a second framing of the food sustainability challenge, the end point in the supply chain, the consumer, becomes the focus of concern. Central to this perspective lies the conviction that excessive consumption, particularly of high-impact foods such as meat and dairy products, is a leading cause of the environmental crisis we face. Technological improvements alone will not be able to address the problem.

This view is shared by many within the animal welfare and environmental movements⁽⁻⁾. These stakeholders base their arguments on academic studies that argue, to varying degrees, for demand restraint⁽Reference Foley, Ramankutty and Brauman ⁶,Reference Williams, Audsley and Sandars ⁷,Reference Audsley, Brander and Chatterton ¹³,⁻⁾.

For example, one study concludes that if consumption is not curbed globally, then given current dietary trends in demand, agricultural emissions are set to rise even when a broad range of production-side mitigation measures are deployed⁽Reference Popp, Lotze-Campen and Bodirsky ⁶²⁾. Another argues that by 2050, livestock sector growth could push the planet to the point where humanity's biological existence is threatened. It concludes that per capita meat consumption in 2050 may therefore need to be between 20 and 40 % of what it is today⁽Reference Pelletier and Tyedmers ⁶³⁾.

While demand may need to be restrained for environmental reasons, this perspective also highlights research finding that reduced consumption of livestock products would actually benefit health⁽Reference Friel, Dangour and Garnett ⁶⁴⁾. Unlike the production efficiency framing, the demand restraint perspective very explicitly links the health and environmental agendas, often viewing the relationship as synergistic. Thus, the GHG intensity of livestock farming is presented in tandem with arguments that excessive meat and dairy consumption undermines health. Support for this position is found from studies (generally undertaken in developed countries and in urban areas) finding an association between diets rich in animal products (specifically red and processed meat) and various negative health outcomes⁽⁻Reference Pan, Sun and Bernstein ⁶⁷⁾.

Demand restraint stakeholders argue that largely plant-based diets are healthier, citing studies showing that people who eat fewer animal products, and vegetarians, are often healthier across a range of indicators, although the reasons for this may be complex; for example, they tend to be more health conscious in general⁽Reference Millward and Garnett ⁶⁸⁾. They also cite studies showing that plant-based diets can supply an adequate balance of key nutrients at lower GHG 'cost' than meat-dominated diets⁽⁻Reference Edwards and Roberts ⁷²⁾. It has also been argued that how much as well as what kind of food people eat also has environmental relevance; obesity carries an environmental cost. For example, studies conclude that a reduction in obesity could yield environmental benefits through the following main pathways: less consumption means that less food (especially livestock) production is needed; reduced passenger weight reduces the amount of energy required to fuel vehicles; and finally, less food is wasted since less food is produced overall (wasted food represents a waste of embedded emissions)⁽Reference Edwards and Roberts ⁷²,Reference Michaelowa and Dransfeld ⁷³⁾. Measures to address the problem could yield both environmental and health dividends.

Notably, while this perspective strongly emphasises the diet-related chronic diseases that are associated with animal products and widespread in many parts of the world (particularly cities),⁽⁾ it focuses less on the ongoing problem of hunger and micronutrient deficiencies that still affect millions of poor people worldwide, especially in rural communities. Importantly, the context for studies comparing vegetarians or low-meat eaters with their high meat-eating counterparts, is one where citizens typically have access to a diverse range of plant-based foods including vegetables, fruits, legumes and meals specifically formulated for vegetarians. The situation is very different in low income developing countries: diets are often monotonous and lack diversity. The positive nutrients found in animal products such as Ca, Fe and Zn, are often of critical importance, particularly to children⁽Reference Dror and Allen ⁷⁵⁾ while livestock can support livelihoods in other ways, with beneficial consequences for health (discussed later). Hence the health-environment synergies obtainable from reduced animal product consumption are highly context dependent. Much depends on what else is, or is not, being eaten and advocates of the demand restraint perspective do not, as yet, have a coherent vision of what a 'healthy sustainable' diet looks like in very low income settings.

Finally, much is made, by restraint advocates, of the point that there is enough food in the world to feed everyone, in contrast to the 'more food' emphasis in the efficiency perspective. The challenge is therefore to address inequitable and resource-intensive consumption patterns⁽⁾, a view developed further in the third perspective, later, but a sophisticated analysis of how structural inequalities might be addressed is lacking. Nor is it clear as to what mechanisms are needed to alter behaviour, apart from some preliminary advocacy of health- or livestock-related taxes⁽Reference Mytton, Clarke and Rayner ⁷⁷,Reference Wirsenius, Hedenus and Mohlin ⁷⁸⁾. Both these gaps reflect the lack of attention that this perspective has received from within the mainstream research and policy community. There are signs, however, that this may change. Increasingly, generally cautious international observers, including the United Nations Development Programme⁽⁾, the United Nations Environment Programme⁽Reference Hertwich, van der Voet and Suh ⁸⁰⁾ the Convention on Biodiversity⁽⁾ and the UK Government's Foresight Programme⁽⁾ some of whom are more traditionally 'productionist' in their views⁽⁾, are starting to recognise that consumption issues merit further consideration.

The values underpinning this demand restraint perspective are varied. For some, the conclusion that demand needs to be moderated is simply the inescapable conclusion to be drawn from the data: without reductions in livestock consumption and associated consumption, the mitigation figures simply do not add up. However, others may have a more overtly moral agenda: greed, the perceived insatiability of human desire itself, is the core issue. Freedom is, by this framing, defined as freedom from the ills of consumption. Thus, for many demand restraint advocates their vision of a good life is one that explicitly challenges the status quo, with its emphasis on consumption and growth.

For some too, technological approaches to reducing environmental impact may themselves be problematic: technologies such as genetic modification are 'part of the problem' rather than, as for the efficiency perspective, a solution. Technology is being used to broach 'natural' limits, whereas the priority should be to respect these limits by shrinking the space which human subjects take up within it. Concerns around animal rights and animal welfare are often added to the mix; stakeholders may reject the industrialised farming that is being advocated as a way of improving the environmental unit efficiency of production or, more fundamentally, even the idea of killing animals for food.

The socio-economic challenge: improve governance

The production efficiency focuses on changing patterns of production; the demand restraint perspective on excessive consumption. The food system transformation perspective considers both production and consumption in terms of the relationships among actors in the food system, interpreting the problem as one of 'imbalance.' The concern lies not just with production, and not just with consumption: it is the outcome of unequal relationships between and among producers and consumers, across and within countries and communities. This inequality gives rise to the twin problems of excess and insufficiency that are played out both in the environment (over- as well as under-application of agricultural inputs) and in health (obesity and hunger). The problems we face are thus socio-economic rather than simply technical or a consequence of individual decisions: they are the outcome of the dynamic interactions among natural, technological, behavioural and economic systems.

Within this perspective can be found a broad spectrum of opinions, some more radical than others in their analysis of the problems and vision of the solutions. Some adopt a macro perspective, focusing on trading relations between nations, while others are concerned with local contexts. For all, though, the central argument here is that food system sustainability can only be achieved by changing the socio-economic governance of the food system. A full spectrum of interventions will be needed, including 'hard' measures such as regulations and fiscal instruments, as well as 'soft' approaches such as voluntary agreements, awareness raising and education⁽,⁻⁾.

This framing of these issues is markedly more rural-centric than the other two perspectives which are essentially concerned with the supply-side needs and consumption patterns of urban populations. The system transformation perspective is focused to a far greater extent on low income rural populations in developing countries, the poorest of the poor.

It also places strong emphasis on all four key dimensions of food security⁽⁾. Unlike the efficiency perspective it privileges not just the 'technical' supply of nutrients but also the requirements of accessibility (incorporating affordability), utilisation (local environmental conditions and pre-existing health status) and the stability of these factors over time. Differing from the demand perspective too, it emphasises that nutritional outcomes are not just the consequence of what foods are or are not consumed, but also of who produces them, where and for whom. Thus, an argument is often made for altering the terms of trade between nations, and particularly for ending subsidies paid out to food producers in developed countries. For low-income countries, the focus is on production to improve self-sufficiency and on fostering intra-regional trading.

Many within this perspective advocate a central role for smallholders (particularly women) in farming a diverse range of indigenous crops and livestock breeds for local markets⁽,⁾. More localised, diverse systems are seen as better able to deliver the full range of micronutrients needed for good health than global supply chains which produce and distribute a simplified range of processed, energy- and fat-dense commodities⁽Reference Toledo and Burlingame ⁹⁰,⁾ however fortified. Moreover, these systems of provisioning (encompassing all food chain stages and actors rather than just the technical act of production) generate income for smallholders, who can then spend their earnings on food or on other essentials, including health care and education, fostering a positive cycle of health and development⁽Reference De Schutter ⁹²⁾.

The development of institutional and social capacity through the creation of local food provisioning systems is seen as critical; it is the key to good nutrition and human well-being. Fortification and biofortification strategies are supply-side approaches that may have a role, but the larger challenge is to address the inequality inherent in the food system which gives rise to these fundamental problems of dietary simplification and inadequacy⁽Reference Johns and Eyzaguirre ⁹³⁾. Similarly, the activities of 'big food' to address micronutrient deficiencies through public-private partnerships are often treated with suspicion for this perspective because they are seen as perpetuating power imbalances: destroying local production, undermining local relationships and provisioning systems, eroding local food cultures and selling processed foods, whose processing is cynically designed to increase the profits of the companies themselves⁽,⁾.

As regards the environment, many within this perspective argue for organic or 'agro-ecological' approaches as these generally incorporate social objectives around principles of fairness and are assumed to be more environmentally benign⁽Reference Toledo and Burlingame ⁹⁰,Reference Fischer, Batáry and Bawa ⁹⁶⁾. The latter assumption has, however, been challenged since yields from these systems tend to be lower, meaning that more land is needed for a given volume of food production. This in turn has implications for CO ₂ release and biodiversity loss⁽Reference Phalan, Onial and Balmford ⁹⁷,Reference Burney, Davis and Lobell ⁹⁸⁾. Moreover, the environmental implications of a scaling up of smallholder production are not given much consideration: while an increase in small-scale livestock production may benefit local communities, it will nevertheless generate GHG emissions and other environmental impacts. Similarly, while greater production and access to local indigenous foods may offer benefits for smallholder livelihoods and people's health, consumers may nevertheless choose to reject these foods in favour of mass marketed, processed products.

In conclusion, the priority for this perspective is to alter the terms of trade between nations, between producers, and between producers and consumers. There is a stronger emphasis on fair trade between nations, greater self-sufficiency, and on the development of local food systems and markets producing a diverse range of nutritious foods. More support is advocated for rural development, with agriculture a central plank in this agenda. Food consumption is more closely linked to what regions are able to produce and there is greater diversity, across the world, in local food cultures. Greater regulation of multinational corporations is needed, together with a greater role for publicly supported research and development, agricultural extension and other initiatives. Freedom, for this perspective, is freedom from injustice.

This perspective shares the redistributive morality of the demand restraint perspective but perhaps goes further in its assumption that the 'underdog' is somehow inherently more likely to farm and consume within environmental limits; an assumption that is certainly open to challenge. It can romanticise the small scale and local, failing to subject these systems to the same critical scrutiny as it does to commercial systems. Thus, while emphasis on improving rural livelihoods at one level reflects pragmatic recognition of how millions of people live today, for many within this perspective, agrarianism is perhaps synonymous with the good life. Both well-being and sustainability are achieved through the harmonious integration of human subjects with nature through rural living and yet people are flocking in their millions to the cities in the hope of a better life.

Conclusion

Each of these three frames on the food sustainability problem has insights to offer, as well as weaknesses and inconsistencies. These may sometimes go unrecognised by stakeholders, who are too immersed in a particular frame to recognise its shortfalls or the merits of an alternative approach. Entrenched positions, ongoing disagreements, and inaction are the result.

A key strength of the efficiency perspective is its pragmatism. It focuses attention on what can be done now, through better technologies and good management, to address immediate nutritional and environmental problems. It injects a much needed optimism into the discussion on food. However, its equation of more food with greater food security is too simplistic, as is its assumption that increases in the unit efficiency of production will compensate for the environmental impacts of increased demand. The effects of product reformulations and so forth on obesity are unclear; such approaches may simply entrench patterns of over-consumption that drive further environmental damage. While in some ways, the efficiency approach suggests a highly democratic vision, a better material life for more people, its implementation may have the effect of strengthening existing power relations in the supply chain that perpetuate inequalities.

The value of the demand restraint approach lies in its emphasis on the need for absolute rather than just relative reductions in emissions; on highlighting the role of consumption patterns on environmental impacts, and on the need to address environmental and nutritional problems together. These together represent important challenges to the production efficiency approach. However, it can lack nuance in its approach to livestock, while the problem of undernutrition in low-income countries requires far more attention. If environmental sustainability is only possible in a situation of severely reduced livestock production, then we need to consider carefully what systems of food production are needed to deliver such low impact, healthy diets and what policies are needed to effect the necessary changes.

The food system transformation offers a necessary critique both of the efficiency and demand restraint perspectives. It focuses on the structures, systems and relationships that underpin food production and consumption, highlighting the way that unequal power relations influence both environmental and health outcomes. However, it can at time romanticise smallholder production and while this perspective is good at identifying the complex nature of food system interactions, this very complexity makes it difficult to identify specific ways forward.

Policy makers are starting to recognise that the 'reality' is a composite of perspectives⁽⁾ and, as emphasised earlier, these framings do not represent ideological positions (at least for most people) but rather inclinations or tendencies that stakeholders manifest when discussing the food problem. Most institutions or individuals will not adopt one perspective alone, to the exclusion of the others.

This said, within most mainstream circles the production efficiency approach still tends to overwhelm the others. Far too little attention is paid to the nutritional quality of what people consume, to the potential that dietary changes can play in addressing health and environmental problems together, or the inequities in the food system.

This imbalance needs to be addressed. The priority for the future is a nutrition-driven food system that sits within environmental limits. This will certainly require efforts to increase the environmental efficiency of food production. However, this approach on its own will not deliver a sustainable food system. Equal attention needs to be paid to issues raised by the other framings. How can demand for foods with high environmental impact be moderated and the supply and consumption of more diverse plant-based foods increased? How can we develop systems of governance that deliver on production and consumption objectives while promoting fairness and justice? These are politically far more challenging. To address them demands a broad interdisciplinary research effort, drawing upon the skills of nutritionists, social scientists, the international development community and economists. It is essential, too, to pay more attention to the values that different stakeholders bring to the debate on food sustainability. These are the source of much disagreement and miscommunication; but by identifying values that are common among apparently very different stakeholders it may be possible to resolve some differences and make progress.

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Food sustainability: problems, perspectives and solutions | Proceedings of the Nutrition Society | Cambridge Core

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For many policy makers, climate change is the major environmental problem we face, and here the food system's contribution is considerable. Estimates find that the food system as a whole contributes between 15 and 28 % to overall GHG emissions in developed countries, with all stages in the supply chain, from agricultural production through processing, distribution, retailing, home food preparation and waste, playing a part( ).

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How do invasive species, such as lionfish effect biodiversity?

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How do invasive species, such as lionfish effect biodiversity?

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What are dead zones and how do they effect the ocean?

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What are dead zones and how do they effect the ocean?

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A cold March wind blows across the Gulf of Mexico, throwing waves carrying red tide, a bloom of toxic algae, into Dan Leonard’s sun-lined face. Leonard, wh