HealthDay News — Increases in glycemic load are tied to long-term weight gain, study findings published in the American Journal of Clinical Nutrition indicate.

“Dietary guidelines recommend interchanging protein foods (e.g., chicken for red meat), but they may be exchanged for carbohydrate-rich foods varying in glycemic load (GL),” noted Jessica D. Smith, MD, of Tufts University, Boston, Massachusetts, and colleagues.

To determine how changes in intake of protein foods, GL, and their interrelationship influence long-term weight gain, the investigators culled 24 years of diet information from 120,784 United States health professionals.

At the outset, all were healthy and normal-weight, on average. Over time, people’s weight crept up — as it tends to with age — but the odds differed depending on the typical quality of their protein and carbohydrates. That was the case even when the researchers accounted for other lifestyle factors, including overall calorie intake.

Men and women who ate lots of nuts, peanut butter, fish, yogurt, and low-fat cheese tended to lose weight. Sugary drinks and refined or starchy carbohydrates — including white bread, potatoes and white rice — had the opposite effect. In general, the researchers reported, adults gained more weight as the glycemic load in their diets rose.

More specifically, every 50-unit increase in a person’s daily glycemic load — the equivalent of two bagels —was tied to an extra pound gained over four years. Certain foods — like eggs and cheese — were connected to weight gain only if people also boosted their intake of refined or starchy carbohydrates. Red and processed meats, meanwhile, were also tied to weight gain.

“A lot of people still think you need to avoid fat to lose weight,” Dariush Mozaffarian, MD, of Tufts University and the Harvard School of Public Health in Boston, told HealthDay. Now, Mozaffarian worries that “count calories” is the new “low fat.”

Putting calorie counts on menus, he said, could send consumers the wrong message: If that deli sandwich has a relatively low calorie count, people may assume it’s a good choice — even if it’s mainly processed meat and refined carbohydrates.


  1. Smith JD et al. Am J Clin Nutr. 2015; doi: 10.3945/​ajcn.114.100867