Volume 80, Number 5 September/October 2009
Summary
Interest in curbing the obesity epidemic has focused on dietary strategies, including increased protein intake, to achieve and maintain a healthy body weight. It generally is accepted that calorie-for-calorie, protein intake increases satiety (a feeling of fullness) to a greater extent than either carbohydrate or fat under most conditions. This protein-induced satiety may lead to improved appetite control, reductions in energy intake, and, over time, better weight management.
A review of short and longer-term energy balanced, weight maintenance studies indicates that increased dietary protein (18-30% of energy) provided in single meals and throughout a typical day of eating leads to increased satiety and, in some studies, reduced daily energy intake compared to a protein intake of 10 to 15% of energy. Since these amounts of protein are within the Institute of Medicine’s Acceptable Macronutrient Distribution Range for protein (10-35% of energy), these findings suggest that increased satiety can readily be achieved using typically consumed foods and prescribed diets.
During longer-term studies of energy restriction as well as during weight-maintenance (after weight loss), dietary protein at a level of 18% of energy or higher has been demonstrated to play a beneficial role in weight loss and/or subsequent weight maintenance, in part through increased satiety, compared to lower protein diets (15% of energy).
Researchers have proposed several mechanisms to explain protein-induced satiety, including increased energy expenditure through increased thermogenesis and changes in the concentration of peripheral and central “satiety” hormones. However, additional research is needed to better elucidate the specific mechanisms contributing to the effect of protein on satiety.
Research demonstrates that increased intake of dairy proteins (casein and whey) and dairy foods enhances satiety, although more studies are needed to determine if the favorable effect of dairy proteins and dairy foods as shown in single meals or preloads on short-term subjective satiety, food intake, and intake regulatory mechanisms can be achieved from usual serving sizes of dairy foods. However, consuming the recommended three servings of low-fat and/or fat-free dairy foods such as milk, cheese, and yogurt throughout the day can help achieve a higher protein intake which, as demonstrated by research, increases satiety and may potentially provide weight management benefits. In addition, the increasing availability of foods and beverages incorporating dairy proteins (e.g., whey protein) as ingredients provides another way to increase protein intake to achieve satiety and weight management benefits.
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