Anyone who has gone on a diet has likely heard some version of the old adage “calories in, calories out”: Burn more calories than you consume and you’ll lose weight — simple as that.
Except that it’s not. A growing body of research suggests that for a lot of people, long-term weight loss isn’t merely a question of cutting calories, especially when not all calories are created equal. But even as medical understanding of weight loss evolves, doctors and nutritionists say many patients still hold deeply rooted misconceptions about dieting.
We asked five experts what patients should know about the latest advances in understanding weight loss and which myths about dieting won’t go away. Here’s what they said.
Bariatric endocrinologist and medical director of medical weight management for Northwestern Medicine Delnor Metabolic Health and Surgical Weight Loss Center, Chicago
I believe the biggest recent shift in understanding weight loss revolves around the thought that focusing on the needs and nuances of each individual can lead to better long-term results.
One of the misconceptions I often hear in my practice as a bariatric endocrinologist is “I can lose more than 100 pounds with diet and exercise.” While patients can be successful with lifestyle changes, large weight losses are not very common. The average weight loss for someone on a traditional diet is about 5 percent to 10 percent of their body weight. For a 250-pound person, that would be 12 to 25 pounds. There are changes in hunger and fullness hormones past this point which impact continued weight-loss efforts. Working with a specialist with a knowledge of these hormones can be the best way to overcome this.
Sustainable weight loss is not accomplished through dieting, but rather through a series of long-lasting lifestyle changes. Even a weight loss of only 5 to 10 percent of body weight leads to significant improvements in health.
Clinical psychologist and founder of the Anti-Diet Plan, New York City
More and more we’re starting to understand that dieting doesn’t work, and intentionally pursuing weight loss can lead to a whole lot of problematic outcomes, both psychologically and medically, like increased risk of an eating disorder, mood symptoms, body dissatisfaction, metabolic disease and even increased mortality. What we’ve been telling people in terms of this “calories in, calories out” model is not only ineffective but actually harmful to people.
The most common misconception is that weight loss is going to be this magical panacea for health. A lot of the things people are seeking from weight loss can be worked on at their current body size.
Fitness is a great example — I have a lot of patients who say, “I have to lose this weight because I want to be more fit. I can’t walk a block without being out of breath.” That’s really about fitness; it’s not so much about weight. If that person is only focused on weight loss, they might wait until they get down to some magical weight before they make any changes in physical activity. But if we say, “OK, let’s separate this out from weight loss and start working toward that goal now,” that can often be accomplished.
Owner of Elyse Metelka Nutrition, New York City
MS, RD, CDN
People are often surprised when they find out that I’m a registered dietitian who doesn’t believe in dieting. That’s because I know that diets don’t work. Many dietitians have been moving away from diet culture and toward a non-diet approach. This is the biggest change I’ve seen in the nutrition and dietetics community.
While dieting can lead to short-term weight loss for some, the majority of dieters fail to keep the weight off in the long run. Some even gain back more weight then what they originally lost on their diet.
Dieting involves restrictions and rigid rules that are not practical and that set dieters up for failure. On top of this, our bodies fight back against diets. Food deprivation from dieting slows down metabolism and increases hunger signals that lead to an overwhelming preoccupation with food and intense cravings, which often results in binge eating and feelings of guilt and failure, which can ultimately result in weight gain. When you decide to let go of the food restrictions and judgments that dieting teaches, such as labeling foods as “good” or “bad,” you can begin to reduce the guilt you feel surrounding food and begin to trust your own body’s natural cues of hunger and fullness.
Caroline M. Apovian
Director of nutrition and weight management at Boston Medical Center and professor of medicine at Boston University School of Medicine, Boston
Somehow, people still think today that all you have to do to lose weight is to stop eating and exercise more. If it was that easy, then everybody would do it. There was one paper that was published in the New England Journal of Medicine showing that if you take people with obesity and you put them on a very low-calorie diet and they lose weight, and then you follow them and measure their hunger hormones, you find they are more preoccupied with food than before. They become preoccupied with food as if they’re starving.
That study really showed how difficult it is to keep weight off. Thirty or 40 years ago, we thought that you just had to go on a diet, lose the weight and you were fine, and people who couldn’t do that were considered to be gluttons. We still have these kinds of biases against people with obesity. Many people, even doctors, will view people with obesity and think to themselves, “Gee, this must be a lazy person who doesn’t exercise and eats junk all day long.” It’s not true; part of it is very physiological.
Faculty in the UCLA Department of Medicine and assistant director of the UCLA Weight Management program, Los Angeles
Over the past several decades, people have started to move away from the idea that every calorie is the same. It has become more evident that a balanced diet with lots of vegetables, adequate protein intake and whole grains is extremely beneficial beyond just weight loss.
Many people also do not realize that when they lose weight, they do not just lose fat, but they also lose muscle. One of the best ways to combat muscle loss is to take in adequate protein and try to improve physical activity levels. This loss of muscle mass can slow down your metabolism.
People also often believe that when they lose weight, they can go back to their previous eating habits. However, in order to maintain their weight loss, they will have to continue to eat less than they did previously, because their body does not need to support the same weight as before. Given some amount of muscle loss during the weight loss process, their metabolism is also slower than before.
Responses have been condensed and lightly edited.