The American Meat Institute says 772 families, including 938 adult family members and 827 children, participated in the study examining different diet types, making it the largest controlled random study in the world.
Of the 938 adult participants, 548 completed both the initial weight-loss phase and the subsequent six-month diet intervention where they were assigned to different diet types. The average weight regain among the participants was 0.5 kg, but there were significant differences from diet-type to diet-type.
The group on the high-protein diet with a low glycemic index (GI) were the only people who maintained their weight after the initial 11 kg weight loss and did not regain weight. In comparison, those in the low-protein/high-GI group showed a weight gain of 1.67 kg.
Fewer participants in the high-protein, low-GI group dropped out of the project than in the low-protein, high-GI group, the study also noted.
“This may be due to a low-GI diet resulting in slow digestion and thus more stable blood glucose levels so that you feel good,” said study author Thomas Meinert Larsen. “Also, proteins result in greater satiety than carbohydrates and fat so that they did not feel hungry.”
Results of the study were recently published in the New England Journal of Medicine.