Does Overeating Make You Fat?

A practicing endocrinologist weighs in on conventional dieting wisdom.

Fried buffet, from Shutterstock
Fried buffet, from Shutterstock

This article is based on a Science Friday interview and was originally published on

Dr. David Ludwig, a practicing endocrinologist at Boston Children’s Hospital and a professor of nutrition at the Harvard School of Health in Boston, says our conventional wisdom about losing weight may be completely incorrect.

“Overeating doesn’t make you fat. The process of getting fat makes you overeat,” Ludwig says.

The health expert has just written a book called Always Hungry in which he lays out a series of new guidelines on dieting, healthy eating and weight maintenance.

“What is the most difficult problem that arises on a diet? People get hungry and, according to the conventional model, we’re supposed to ignore the hunger, use discipline, and stick to the diet,” Ludwig says, “Because it sounds so simple, people who can’t do it—which are 90 percent of the country or more with a weight issue—are blamed for the problem.”

The key to maintaining a healthy weight, Ludwig insists, is not discipline, but getting our bodies to work correctly.

“Body weight is really much more about our biology than our willpower,” Ludwig says. “Something has triggered our fat cells to suck in and hoard too many calories. The fat cells are in communication with the bloodstream and they actively can either take in or release calories. But if fat cells are driven into a feeding frenzy, in fact they hoard too many calories, and there are too few in the bloodstream. So the brain recognizes that as a metabolic crisis. It doesn’t see that there’s too many calories in the fat cells…So the brain does what it’s supposed to do, what it’s evolved to do, which is it makes us hungry. And it slows down metabolism, making us more and more efficient.”

Instead of following the conventional mantra to “eat less and exercise more,” Ludwig suggests we re-train our bodies.

“Cutting back on calories only makes the situation worse, creating a battle between mind and metabolism that we’re destined to lose. So really the solution is to think about weight issues like we do about any other problem,” Ludwig says.

Ludwig’s system of healthy weight maintenance involves a three-step approach to re-training our bodies. In the first phase, he suggests people eliminate grains, potatoes, and added sugars from their diet for two weeks. In phase two, he re-introduces whole kernel and processed grains. In phase three, he adds back more processed carbohydrates, depending on people’s ability to handle them.

“The highly processed carbohydrates we’ve been eating and a few other dietary and lifestyle influences have caused hormonal changes in the body, especially involving insulin that drive fat cells into a feeding frenzy. So they feast and the rest of the body starves,” Ludwig says, “We think of obesity as a state of excess. But it’s really an issue of starvation to the body and cutting back on calories makes that worse. So instead we propose a much higher fat diet, a three phase program and some other dietary changes and some lifestyle supports that also help the fat cells calm down. When that happens the calories flood back into the body and you feel much more energetic, cravings decrease, energy expenditure increases. And you start losing weight with your body’s cooperation, not against it.”

According to Ludwig, getting the body onto a healthy diet is important not for just weight maintenance, but for a host of other health issues.

“What happens with obesity, with insulin resistance, is that the fat cells start to overgrow their blood supply. Some of them may actually suffer dysfunction or even die,” Ludwig says. “And it creates inflammation, but in this case there’s no bacteria to kill that inflammation which becomes chronic fat tissue and then starts secreting into the rest of the body…when that inflammation spreads to the lining of the blood vessels that can contribute to atherosclerosis and heart attack. When it goes to the pancreas it can add contribute to diabetes. If it goes to the brain, neurodegenerative diseases. So we’re now seeing an epidemic of Alzheimer’s which some people are now calling type three diabetes.”

Meet the Writer

About Elizabeth Shockman

Elizabeth Shockman is a freelance journalist who lives in the Twin Cities. Previously she worked as a PRI staff member and freelancer, reporting primarily from Moscow and around Russia.

Explore More

Why We Need Body Fat

Body fat is a highly specialized organ, critically important for health and longevity.

Read More