A modest increase in protein content and a modest decrease in glycemic index values allowed study subjects to maintain 10-kg weight loss better than did other dietary manipulations, according to a randomized trial.
More subjects also were able to continue losing weight while consuming this combination of high-protein, low glycemic-index foods, according to the University of Copenhagen and associates in the Diet, Obesity, and Genes (Diogenes) study.
The Diogenes study was designed to assess the efficacy of five different maintenance diets in preventing weight regain after obese subject lost at least 8% of their body weight during an 8-week low-calorie diet. The maintenance diets all contained moderate amounts of fats (25%-30% of total energy consumed), all allowed unrestricted caloric intake, and all attempted to keep alcohol and fiber contents comparable, varying only in their protein content and glycemic indexes.
The study was conducted at research centers throughout Europe. A total of 773 subjects who achieved their target weight during the low-calorie-diet period were randomly assigned to continue a 26-week maintenance phase following a diet low in protein (13% of total energy consumed) with a low glycemic index; a diet low in protein with a high-glycemic index; a diet high in protein (25% of total energy consumed) with a low glycemic index; a high in protein, high-glycemic index diet; or a control diet with moderate protein content and no guidelines regarding glycemic index.
The study subjects received dietary counseling every other week for 6 weeks, and then monthly thereafter. They were given recipes, cooking instructions, behavioral advice, and a teaching system to help them achieve the targeted composition of macronutrients.
Even a modest increase in dietary protein or a modest reduction in glycemic-index values was sufficient to minimize weight regain and promote further weight loss in obese patients after a successful weight-loss diet.