Obesity and eating disorders are two distinct conditions, but they are intertwined in many ways. Some people with eating disorders might tend to gain weight leading to obesity. People with obesity might also have disordered eating habits.
“Eating disorders have to do with your mental health and emotions. There may be different causes for this,” says Umme Sana, nutritionist, Rustic Wisdom, Bengaluru. Being conscious about one’s looks is the primary cause of eating disorders, points out Sana.
The science behind hunger and obesity
“Hunger and obesity are interrelated,” says Dr Mehr Prasad, endocrinologist, Fortis Hospital, Chennai. Hypothalamus is a part of the brain that controls hunger and satiety through the interactions of the hormones, ghrelin and leptin.
Sana describes the role of these hormones:
- Ghrelin – This hormone stimulates hunger
- Leptin – This hormone suppresses hunger
In people with obesity, the level of leptin is suppressed and the level of ghrelin is increased. Unable to attain satiety due to ghrelin, people tend to overeat.
Dr Prasad explains that satiety works in two ways – mentally you feel like you have eaten enough, and physically you feel full. Satiety also depends on the kind of food you eat. Protein and fibres give a feeling of fullness to a greater extent than carbohydrates. So, with less leptin and more ghrelin, people could end up eating large quantities of carbohydrates.
Ghrelin and leptin affect the energy balance – the state at which the energy in (calories consumed) equals the energy out (calories expended).
Dr Prasad points out that it is the difference in the energy equation that causes obesity. The calories that you can’t burn tend to accumulate and are converted into glucose and fat. They get collected in the liver and other places. To lose weight, one needs to create a negative energy balance for the fat to start breaking down.
The major eating disorders related to obesity are:
This eating disorder causes binge eating, followed by compensatory behaviours such as purging (vomiting), laxative abuse or excessive exercise to prevent weight gain. “People with this disorder don’t socialise much and fear eating in front of people. They tend to eat a lot, and alone,” says Sana.
The eating disorders that have been most frequently studied in individuals with obesity are binge eating disorder and bulimia nervosa.
Night eating syndrome
This eating disorder causes one to wake up at night to eat. “A person with night eating syndrome consumes more than 25 per cent of their daily calories at night. This can lead to weight gain,” says Dr Sweta Budyal, consultant endocrinologist and diabetologist, Fortis Hospital, Mulund.
Binge eating disorder (BED)
This eating disorder causes one to eat large amounts of food in a short period. “This can lead to obesity. There is no control over food, so they tend to eat a lot. And they usually eat food that is high in carbs,” says Sana.
“Binge eating disorders can cause obesity,” says Dr Budyal. A study with 152 treatment-seeking individuals with obesity found that those with binge eating disorder had higher BMIs, more severe levels of depression and obsessive-compulsive symptoms, and stronger feelings of inadequacy and inferiority than those without binge eating disorder.
“Eating disorders are serious psychiatric problems. They are way more than just stress eating or emotional eating. They need to be properly evaluated and addressed through proper medications,” says Dr Budyal.
Individuals with obesity and comorbid eating disorders are at higher risk for several medical and psychosocial complications than individuals with either condition alone.
Dr Budyal adds that, if a person with obesity has eating disorders, those should be treated first.
Eat the right things, in the right quantity, at the right pace
Dr Prasad says that there are some things that one can keep in mind when it comes to food. Impulses from the stomach travel to the hypothalamus if you are full. But if you eat too fast, the brain does not get the impulse and you tend to overeat. He also says that people should eat the right things in the right quantity and not the wrong things in excess.
Eating disorders and obesity are closely interconnected. The major eating disorders associated with obesity are bulimia nervosa, night eating syndrome and binge eating disorder. Experts point out that if an obese person has eating disorders, then those disorders should be addressed first.