The obesity epidemic remains a grave concern for public health, with prevalence reaching critical levels to induce a global epidemic. In England alone, nearly two thirds (64%) of adults are overweight or obese, and around a third (30%) of children are overweight and obese. It is common knowledge that obesity has a range of physical co-morbidities such as type 2 diabetes, certain cancers, and cardiovascular disease. But what about obesity and mental health implications? Obesity is frequently associated with low self-esteem, body image disturbances and affective disorders such as anxiety and depression. It is most likely that we as a society have contributed to the obese people feeling these negative psychological repercussions through stigmatisation. This blog post will look at some reasons behind the obesity epidemic that should illustrate why we should be more considerate when we approach the problem of obesity.

The energy balance framework is the commonly accepted theory used to understand the cause of obesity, however, the specific mechanisms through which obesity manifests are still disputed. The energy balance framework (energy balance = energy intake – energy expenditure) postulates that a person of a healthy weight consuming roughly the same number of calories that they expend over a long period of time to maintain a healthy weight. And a person becomes overweight by eating too much and moving too little. Unfortunately, things are not as simple as they seem. We know that obesity is a complex issue, which involves a dynamic interplay of biological, environmental and social/psychological factors.

We don’t have as much control over our weight as we think we do. Granted, eating and exercise are behaviours that can combat against excess weight gain but the biological forces at play are profound and often overlooked. For example, we all know that our genes are responsible for our hair colour, skin colour and all other bodily appearances. It is a similar story for our body type and subsequent weight, which is not far from being as hereditary as our height. Studies using twins have helped to show the influence of genes on weight because twins are genetically identical and so genetic comparisons and conclusions can be made. Research has revealed that that shape and body weight genetic heritability in twins is around 70%. The genes are instructing certain biological functions (i.e. metabolism, fat mass accumulation) which are outside of our control that influence the energy balance paradigm, and subsequently our weight.

Even when we do make a conscious effort to make a change and start exercising for example, research has shown that there is biological variation in response to exercise. This means that people on identical exercise routines produced markedly different weight loss, and some even gained weight! Why this is the case remains equivocal, but it is likely to be a consequence of genetic variation.

Additionally, our human physiology and behaviour have not adjusted to the current obesogenic environment. The obesogenic environment promotes the overconsumption of cheap and dense calorific food, whilst demoting physical activity. The current obesogenic environment has manifested so rapidly that our physiology has not adjusted accordingly. Human beings have evolved over many millennia to defend against weight loss because this was an adaptive trait that aided survival in times of food scarcity. Our ancestors who had the appropriate physiology to survive the harshest famines would be successful in passing on their hardy genes to the next generation and so on.


The obesogenic environment is especially prevalent in Western society, which throws countless junk food adverts and promotions our way. Marketing strategies target vulnerable and susceptible children with the intention to manipulate them into a life-long subscription of their sugary and fatty products. The younger they catch them, the more reliable and sustained the company’s income. The obesogenic environment has arisen in the past 20 to 30 years and this positively correlates with the rise of obesity. This means that as the obesogenic environment has grown, so too has the prevalence of obesity, indicating the influence of environment on subsequent weight gain.

Like with many aspects of physical and mental health the poorest are the most susceptible to obesity, especially with regards to children. In England, obesity rates for the most deprived children are nearly twice as high compared to those who are least deprived. There is a similar trend for female adults but there is less disparity between deprivation and obesity in male adults. The child obesity stats are more alarming when we consider research that has shown that children who are obese are 5 times more likely to obese when they are adults. This indicates that children from poorer backgrounds are set up to fail in relation to their physical and mental health, because their chances of becoming and remaining obese are a lot higher thus leaving them susceptible to a host of physical and mental co-morbidities associated with obesity. Deprivation appears to be the societal influence which negatively impacts on obesity.

We have only just scratched the surface on the underlying causes of obesity, and much more needs to be understood. But the complex nature of obesity is not appreciated in the public eye, because it is much easier to point the finger rather than confront ignorance and misinformation spread significantly by mass media. Far too often blame is put on the individual and their behaviour for their (over)weight status, and obese people are frequently discriminated against for being lazy, gluttonous, ill-disciplined or exhibiting low will power. These views are subsequently reinforced within the workplace, exercise areas or in educational settings, which leads people to think that obesity is a choice. Research has shown that people often hold negative perceptions of both overweight and obese individuals that are not necessarily substantiated, in other words a prejudice is formed. But considering the evidence, we need to discard the stereotypes surrounding obese people otherwise the stigma that is created only antagonises the situation, thus compromising obese individual’s physical and mental health.