In America’s on-again, off-again love affair with weight-loss regimes, few have seen their fortunes wax and wane as much as the high-protein diet. But researchers have been reluctant to dismiss protein’s potential, and they’re building a body of evidence that may well confirm the macronutrient’s role in weight management.
Wants vs. needs
The idea that protein plays a role in overall health is hardly new. As David B. Allison, Ph.D., professor, Department of Biostatistics, University of Alabama, Birmingham, says: “Everybody needs protein. It’s essential to survive.” The Food and Nutrition Board of the National Academy of Sciences, Institute of Medicine (IOM), Washington, D.C., set its most-recent dietary reference intake for protein at 46 grams per day for females ages 19 to 70, and 56 grams per day for males of the same age. These figures apply even to active individuals.
But protein intake can benefit us beyond our baseline nutrition needs. Research has uncovered a role for protein in enhancing satiety, and in stimulating key weight-management hormones. The mechanisms by which it exerts these effects aren’t fully understood, although theories exist. For one, protein digestion requires more energy than fat digestion; this so-called “thermic effect” could lead to a high-protein meal actually burning calories via digestion.
The body shop
“Studies have examined the impact of different levels of dietary protein on weight loss and body composition in diet plans in which groups are matched for the same amount of total calories and energy deficit,” says Matt Pikosky, director, research transfer, Dairy Management Inc.™ (DMI), Rosemont, IL. In these situations, he notes that “while weight loss is similar between the groups, the quality of the weight loss may be different in that the higher-protein group preserves more muscle while losing more fat compared to the lower-protein group.”