Why healthy diet, exercise are not enough to treat obesity

PEOPLE who are obese are often told to eat healthier and exercise more in order to lose weight. But in an article recently published in The Lancet Diabetes & Endocrinology, obesity experts claim the condition is a chronic disease that can be caused by biological factors, meaning many cases may not be cured with a healthy diet and physical activity alone.

    While a healthy diet and exercise may help obese individuals lose weight in the short term, the experts say around 80-95 per cent eventually gain back that weight.

     In the United States (US), around 35 per cent of adults and 17 per cent of children and adolescents are obese. Both the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH) cite a healthy diet and exercise as a primary factor in combatting obesity. But is it really that simple?

     Not according to lead author Dr. Christopher Ochner, assistant professor of pediatrics and psychiatry at the Icahn School of Medicine at Mount Sinai in New York, NY, and colleagues.

     In their article, the experts state that while a healthy diet and exercise may help obese individuals lose weight in the short term, around 80-95 per cent eventually gain back that weight.

    They explain that this is partly because a reduced intake of calories can activate a type of biological “fat-loss defense” that encourages the body to stay at a higher weight.

    According to the authors, this defense mechanism once protected humans when food was scarce. In these modern times, however, humans tend to have higher body weights for longer periods. As such, the defense mechanism drives calorie consumption and fat storage so a higher body weight can be maintained.

    Most obese people ‘unable to override fat-loss defense’ with diet and exercise

The authors say that in a 21st century environment where high-calorie, high-fat foods are the norm, alongside low levels of physical activity, the majority of people who are obese are unable to override the defense mechanism simply through lifestyle changes.

   Dr. Ochner adds: “Although lifestyle modifications may result in lasting weight loss in individuals who are overweight, in those with chronic obesity, body weight seems to become biologically ‘stamped in’ and defended.