WHY DOESN’T THE WEIGHT STAY OFF?
When you lose weight, your body responds by increasing your appetite and reducing the number of calories you burn, Dr Hall said.
He and others have estimated that for every 900 grams of weight you lose, your metabolism slows by about 25 calories per day, and your appetite increases by about 95 calories per day. So in other words, if you lose 9 kg, your body will burn roughly 250 calories less each day while craving about 950 calories more.
To maintain your weight loss through dieting over time, you’ll have to continue eating less while resisting a rising appetite and slower metabolism, which is “increasingly difficult,” Dr Schur said.
The drive to eat more is so strong because our brains “sense that our energy stores are being depleted,” she added, and “that’s a threat to our survival.”
The new weight loss drugs prevent weight regain in part by reducing normal appetite signals, Dr Collazo-Clavell said. But when people stop taking the drugs, the weight returns, probably for the same reasons described above.
Are there health risks associated with dieting for weight loss?
Dieting often results in cycles of weight loss and regain, and some research has suggested that this can be harmful, said Kendrin Sonneville, an associate professor of nutritional sciences at the University of Michigan School of Public Health.
Some, but not all, studies have found that weight fluctuation is associated with earlier death, cardiovascular disease, Type 2 diabetes and depression; however, these studies sometimes include people who have lost and regained weight because of health problems, not just from dieting.
“There’s not conclusive evidence that it’s harmful to go up and down,” Dr Schur said, but there is debate about the possibility.
Dr Sonneville also worries that dieting may put some people at risk of developing an eating disorder. Anecdotally, many people with eating disorders say that their conditions began with dieting, she said. While clinical weight loss trials have not borne this out, those studies have had many limitations and have not fully assessed how dieting affects “people’s relationship with food and their bodies in the long term,” Dr Sonneville said, so more research is needed.
Most people who diet don’t develop an eating disorder, Dr Sonneville said, but even then, their relationships with food can deteriorate if they start “ prioritising weight and nutrition over joy and culture and connection.”
If you have a difficult relationship with food and your body, or if you have experienced binge eating or another eating disorder, Dr Schur said, it is more important to focus on a healthy relationship with food than on your weight.