Not all proteins are alike. Some are digested and absorbed rapidly, while others may impact metabolism and glucose control. Scientists at the Nestlé Research Center, Lausanne, Switzerland, compared the effects of various protein sources on energy metabolism, satiety and glucose control in humans. The full article can be found at the American Journal of Clinical Nutrition
Protein is a beneficial nutrient for weight control not only because it takes more energy to digest and absorb proteins, but also because protein may influence appetite and satiety (the feeling of fullness after a meal). Since little is known about the magnitude of these effects among different protein sources (milk, vegetable or animal proteins), Nestlé researchers conducted a clinical trial to find answers.
Three meals of equal calorie content consisting of 50% protein from whey, casein and soy protein respectively (with 40% carbohydrate and 10% fat), and a fourth, high-carbohydrate (95% carbohydrate) meal were given to healthy adults. Researchers measured the energy expenditure, thermic effect, glycemic response and appetite sensations before and after the four different meals.
Results showed that the protein-rich meals led to a greater energy expenditure and thermic effect than the high-carbohydrate meal, that the effects of whey were significantly greater than those of casein and soy and were accompanied by a trend for greater fat oxidation. All three proteins (in the presence of glucose) significantly lowered peak glycemia after the meal. Furthermore, casein and soy protein lowered glycemia with little, if any, increase in insulin secretion above that of the glucose component of the meal.
“Our study confirmed that protein-rich meals promote greater energy expenditure than carbohydrate-rich meals of equal calorie content.” says Dr. Kevin Acheson, Nestlé scientist leading the study. “These findings strengthen the evidence that increased protein content in the diet promotes weight control. Different protein sources could be used for personalized nutrition needs.”
Nestlé researchers will extend the investigation of these results to the acute and long-term health benefits of proprietary protein sources.
Acheson K, Blondel-Lubrano A, Oguey-Araymon S, Beaumont M, Emady-Azar S, et al. Protein choices targeting thermogenesis and metabolism. American Society for Nutrition, 2011; 93(3): 525-34. doi: 10.3945/ajcn.110.005850