Many people turn to high-protein foods when trying to lose weight because eating protein-rich meals is commonly believed to make dieters feel fuller. Surprisingly, this idea hadn’t been tested on a large scale.
“A good deal of evidence suggests that protein activates satiety hormone release and so should be most strongly tied with fullness ratings, but individual studies are often conducted in small populations or with different approaches that can make interpretation of results challenging,” said lead investigator Richard D. Mattes, distinguished professor, Dept. of Nutrition Science, director of public health, and director of the Ingestive Behavior Research Center at Purdue University, “Our study combined multiple experiments to confirm the presence of an effect.”
The research team used a variety of statistical approaches to make sense of the data. These techniques included a quantitative meta-analysis and a secondary directional analysis using a vote counting procedure. Both the meta-analysis and directional analysis indicated that higher protein loads have a greater effect on fullness than lower protein loads. With the confirmation that protein intake is related to satiety, defined as fullness between meals, modestly higher protein intake may allow individuals to feel fuller between meals.
“Though this study did not specifically evaluate dieters, feeling fuller could help to reduce food intake, an important factor when dieting,” concluded Mattes. “If these effects are sustained over the long-term—and our study only looked at short-term effects—increased protein intake may aid in the loss or maintenance of body weight.”