World Obesity Day falls on 4th March each year1, aiming to raise awareness of the obesity crisis and encourage impactful change to reverse the concerning rise in obesity rates worldwide. The theme for this year focused on ‘changing systems for healthier lives’, drawing blame away from the individual and paying more attention to the systemic failings in developed and developing nations that are contributing to the increasing prevalence of obesity1.
According to the WHO2, 1 in 8 adults worldwide were living with obesity in 2022, with adult obesity having doubled since 1990. Arguably more concerning is the spike in childhood and adolescent obesity, with 160 million individuals aged 5-19 years old and 37 million children below 5 years old living with obesity (as of 2022).
Obesity is a non-communicable disease that’s characterised by abnormal and/or excessive adipose tissue accumulation leading to a high body mass index (BMI) - the BMI definition of obesity varies depending on age and gender2. The disease has been historically associated with high-income countries1, largely attributed to the populations’ increased access to calorie-dense, processed foods that are high in sugars and fats, and heavy reliance on mobilised transport leading to more sedentary lifestyles3, among other interrelated factors (such as urbanisation4, education/awareness5, and income2). 1 in 5 children and adolescents in the USA are living with obesity, leading to an estimated annual medical cost of $1.3 billion6, and nearly 1 in 3 children in the UK are overweight or obese7. Interestingly, obesity rates are highest in lower socioeconomic areas within these high-income nations8, and we’re beginning to see increasing rates of childhood and adolescent overweight & obesity in developing nations1.
Low- and middle-income countries are now tackling a ‘double burden of malnutrition’, experiencing undernutrition as a consequence of high infectious disease rates and overnutrition due to globalisation9 and changes in lifestyle, sometimes within the same regions or even the same families/households1. With the increasing prevalence of obesity across the globe, the WHO declared, as part of the Sustainable Development Goals initiative, a target (SDG 3.4) to reduce global non-communicable disease prevalence (including obesity) by 1/3rd by 2030 through prevention and treatment and promoting greater mental health and well-being10.
The health implications of childhood & adolescent obesity can be experienced both in the short-term (during childhood/adolescence) and long-term (later in life)11, increasing the risk of type 2 diabetes, high blood pressure increasing cardiovascular disease risk, certain cancers, musculoskeletal (particularly joint health) and respiratory health issues (e.g. asthma and sleep apnoea)12. The effects are not limited to physical health however, where childhood & adolescent overweight/obesity can contribute to mental health issues, such as depression or anxiety, and social isolation11-12. Such health implications of obesity are key players in the economic burden that many developed and developing nations are struggling to manage as obesity rates continue to rise2, with arguments that nations are struggling with increasing obesity prevalence due to their prioritisation of treatment-focused interventions (where they treat the individual once they have developed obesity and/or it's associated health complications) as opposed to interventions that emphasise a prevention-first approach (where the prevalence and consequent economic burden of treating obesity would be reduced).
Whilst diet and lifestyle are key players in the development of obese BMI levels2, there are many factors that increase an individual’s risk, including (obesogenic) environments13, familial influence14, income8 and education5,15. Given the interrelated factors involved in obesity risk, some argue that economic systems are the key contributor to obesity prevalence16. Market economies respond to consumer demand, and where the demand for processed food and urbanisation has increased, the consumption of processed food and reduced physical activity (associated with urbanisation) has consequently increased16. Fast-food restaurant density patterns prove a concerning example of this - fast-food restaurants are successful in poorer areas, as the affordability and convenience of fast-food meals are favoured by families with a lower socioeconomic status, due to their reduced income limiting access to healthy foods (which tend to be more expensive), and less time available to cook healthy meals (especially for families where the parents/guardians need to work more than 1 job/long hours to support themselves and their dependents). Due to the profitability of this opportunity, more and more fast-food restaurants are opening in these areas, pushing supermarkets and health-food stores further out of such areas, leading to an increased availability of calorie-dense, processed food and limited access to convenient and locally affordable healthy, whole food options for low socioeconomic families16.
To combat the increasing burden of childhood obesity on public health, the UK government introduced the ‘Childhood obesity plan’ and a soft drink industry levy7, and the US has the ‘reducing obesity in youth act’17. Whilst such interventions have shown some success in encouraging food reformulations and reducing sugar consumption18, they fail to consider the multifactorial nature of obesity, where children and adolescents are still growing up in obesogenic environments and struggling to lead healthy lifestyles due to their socioeconomic status18. Developing nations are also trying to combat increasing childhood obesity rates through national intervention, with examples including, but not limited to, Brazil introducing a school feeding program to improve the nutritional quality of school meals19, and Mexico introducing a soda tax which has proven successful in reducing sugar-sweetened beverage consumption20. The double burden of malnutrition will make tackling rising obesity prevalence more difficult in developing nations however, with weaker healthcare infrastructure and poorer national socioeconomic status acting as additional blockers to successful intervention – such difficulties could explain why low-to-middle income countries are predicted to contribute up to 88% of global childhood/adolescent overweight and obesity prevalence by 203521.
There are strong arguments to suggest that obesity is a systemic issue, as opposed to an issue caused only by an individual’s diet & lifestyle choices, as emphasised by the World Obesity Foundation’s chosen theme for World Obesity Day 20251. This supports the argument that meaningful change and intervention should target systems on a national and local level to reduce obesity prevalence, rather than focusing solely on encouraging dietary/lifestyle changes on an individual level15. The afore-mentioned governmental interventions are a positive start, however they have not proven as successful as one would have hoped18, suggesting that they are not tackling the root cause(s) of the problem. Public health experts argue that a holistic, integrated systems approach is needed22, with prevention-focused interventions taking into account a number of systemic-based causal factors, such as education (for children, adolescents and parents/guardians), socioeconomic status, genetics and biological predisposition, sedentary lifestyles, environmental influence, and cultural differences (particularly focusing on cultural influences on diet and lifestyle).
That said, this would not be an blog on obesity prevalence and prevention/management without addressing the recent rise in medical interventions to promote weight loss, such as anti-diabetes drugs like Metformin, or others including Orlistat or Liraglutide23. Whilst these are available for free on the NHS to individuals who meet certain strict criteria, these are not freely accessible in the USA or most low-to-middle income countries. Additionally, they are not readily available to children or adolescents. Whilst medical intervention has its place in helping those struggling to lose weight by alternative means, their increasingly widespread use by those who are not severely overweight or obese, combined with extensive coverage/promotion in the media, has been arguably detrimental to the body positivity movement, worsening stigma and discrimination24. These societal pressures risk exacerbating the mental health issues and social isolation experienced by overweight/obese children and adolescents. For this reason, such matters need to be considered and mitigated for in new approaches and interventions to prevent and manage obesity risk in children and adolescents.
To conclude, in order to achieve the WHO’s SDG 3.4 target of reducing non-communicable disease prevalence by 1/3rd by 2030, it's clear that future interventions should consider the multifactorial nature of obesity risk, looking to halt the development of adult obesity through prevention & treatment initiatives targeting childhood obesity. Current interventions focus too heavily on individual choice and diet/lifestyle behaviours24, where placing sole blame and responsibility on the individual proves akin to ‘fixing the symptoms without treating the disease’. Effective intervention should focus on prevention as well as treatment, identifying key systemic causes specific to the nation and resolving those through holistic, whole-systems approaches, before targeting individual diet & lifestyle behaviours.
References/Links:
2 https://www.who.int/news-room/fact-sheets/detail/obesity-and-overweight
3 https://www.nber.org/digest/nov07/why-developed-world-obese
4 https://jcrpe.org/articles/doi/jcrpe.1984
5 https://educationinspection.blog.gov.uk/2018/07/18/tackling-childhood-obesity-a-shared-problem/
6 https://www.cdc.gov/obesity/childhood-obesity-facts/childhood-obesity-facts.html
8 https://link.springer.com/article/10.1007/s13679-020-00400-2
9 https://globalizationandhealth.biomedcentral.com/articles/10.1186/s12992-018-0344-y
11 https://health.clevelandclinic.org/long-term-effects-of-childhood-obesity
12 https://www.mayoclinic.org/diseases-conditions/childhood-obesity/symptoms-causes/syc-20354827
13 https://link.springer.com/article/10.1007/s13679-018-0292-0
14 https://link.springer.com/article/10.1186/s12887-024-0464-w
15 https://link.springer.com/article/10.1007/s13679-024-00578-9
16 https://doi.org/10.3945/ajcn.2010.28701E
17 https://www.congress.gov/bill/118th-congress/senate-bill/3171
18 https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-021-12364-6
19 https://www.wfp.org/centre-of-excellence-against-hunger
20 https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-023-15041-y
22 https://link.springer.com/article/10.1007/s13679-013-0072-9