Increased consumption of high calorie processed foods and a shift towards completely sedentary lifestyles has resulted in an increasing rounder population across the world. We are in the grip of a global epidemic, and it has estimated that by the year 2020 obesity will be the single biggest killer on the planet. Obesity rates have risen at least threefold since 1980 in some areas of North America, the UK, Eastern Europe, the Middle East, the Pacific Islands, Australasia and China. Developing countries like India are facing a dual health burden with obesity coexisting with malnutrition. A survey of 83,000 Indian women found that although 33 percent were malnourished, 12 percent were overweight or obese.
Of particular concern is the increasing rate of child obesity, especially in the Asian diaspora. Urbanization in China has lead to harvesting an unhealthy lifestyle, as the Chinese government calculates that 1 in 10 city-dwelling children suffer from obesity. In Japan, obesity among nine-year-old children has tripled. While we do not have any consolidated figures for India, doctors say they are witnessing a clear trend towards an increase in obesity among children. We now know that the biggest global health burden we are facing is dietary in origin and compounded by association with low physical activity levels.
Research has shown that while there is no clear, one-way connection between obesity and depression, a vicious symbiotic cycle is eminent to the extent that they feed off on the mental stability of the afflicted individuals. In fact, there is a bi-directional association between mental health issues and obesity, with an entrenched impact on the risk factors associated with obesity and mental health. Along with that, there are implications of psychological distress caused by weight-related stigma and discrimination, evidence suggests that people with mental health issues are more prone to obesity.
Health problems linked to obesity
Compared to adults with normal weight, adults with a BMI greater than 30 are more likely to be diagnosed with coronary heart disease (CHD), hypertension, stroke, high cholesterol, gout, osteoarthritis, sleep problems, asthma, skin conditions and some types of cancer. Obesity also is an important causal factor in type 2 diabetes, and it complicates the management of the disease, making treatment less effective.
Obesity may also trigger a series of psychological disorders including depression, eating disorders, distorted body image, and low self-esteem. Binge eating may explain, at least in part, the relationship observed between obesity and depression. This may be because binge eating could contribute to weight gain and obesity, which, in turn, may negatively affect mood. Furthermore, recurrent episodes of binge eating are extremely unpleasant for those who experience them and may put the individual at higher risk of clinical depression.
Mental health issues and obesity: the two-way link
The relationship between obesity and mental health issues is a complex one and there exist different theories about the association between the two. Some researchers suggest that obesity can lead to mental health problems, whilst others have found that people with such problems are more prone to obesity. Other studies have found no association between the two.
Results from the most recent systematic review of longitudinal studies point towards bidirectional associations between depression and obesity. Another recent systematic review and meta-analysis found a weak but positive association between obesity and anxiety disorders. Obesity is also associated with an increased risk for a variety of chronic diseases, most of which are associated with depression that in turn can precipitate chronic disease due to diminished treatment adherence and/or response. There is a number of mechanisms that could explain potential casual associations between obesity and mental health issues:
Both obesity and mental health disorders account for a significant proportion of the global burden of disease.
The mental health of women is more closely affected by overweight and obesity than that of men.
There is strong evidence to suggest an association between obesity and poor mental health in teenagers and adults. This evidence is weaker for younger children.
The perception of being obese appears to be more predictive of mental disorders than actual obesity in both adults and children.
Weight stigma increases vulnerability to depression, low self-esteem, poor body image, maladaptive eating behaviours and exercise avoidance.