Eating processed carbohydrates such as white bread, white rice, potato products, and sugar can drive up insulin levels in the body and lead to weight gain. Nutrition expert David Ludwig of Harvard T.H. Chan School of Public Health says that eating fewer of these unhealthy carbs—more so than cutting calories—can help maintain long-term weight loss.

In a January 4, 2019 interview on the radio show “Science Friday,” Ludwig, professor in the Department of Nutrition, discussed a recent study he co-authored that found that, among nearly 200 overweight patients, those who cut carbs from their diets and replaced them with fat increased their metabolism and were able to burn more calories daily when compared with people who ate a high-carb, low-fat diet.

“The standard approach to weight control considers all calories alike,” Ludwig said. “Just eat less and move more—we’ve heard it a thousand times. Our research suggests that a focus on food quality rather than calories may [promote weight loss] more slowly, but it’ll keep you there over the long term.”

Ludwig advised replacing processed carbs with whole fruits and minimally processed grains, “the way that grandparents used to eat.” He added that it’s OK to eat healthy fats. “Fat makes food tasty and it slows down digestion, and doesn’t raise insulin, so in my view, fat should be encouraged, not feared, in a weight-loss plan,” he said.

Listen to the “Science Friday” interview: Are All Calories Created (And Burned) Equally?

Learn more

For overweight adults, cutting carbs may jump-start metabolism (Harvard Chan School news)

Healthy fats help curb cravings for unhealthy carbs (Harvard Chan School news)

Carbohydrates (The Nutrition Source)