are popular in weight loss formulas because they boost metabolism.
However, consuming simple food raises metabolism and some foods are better at inducing thermogenesis than others. In general protein is significantly more thermogenic than carbohydrate or fat. But new research is focusing on differences between protein sources. Swiss researchers tested how ingesting single meals containing whey, casein and soy impacted energy expenditure and fat oxidation. The test meals all contained 459 kcal, and half the calories were from protein isolates derived from whey, casein or soy. There was a control meal containing only carbohydrate. Measurements were taken for 5.5 hr after the meal. Compared to the carbohydrate meal, all 3 protein meals resulted in a significantly greater increase in energy expenditure. When comparing protein meals, whey resulted in a greater increase in thermogenesis than soy and casein. Compared to the carbohydrate meal, whey protein resulted in an additional 34 kcal expended over the 5.5 hr period. Fat oxidation was also higher during whey intake than the other meals. This study confirms that
increases energy expenditure more than an equal amount of
, and that
is more thermogenic than other protein sources.
Acheson KJ, Blondel-Lubrano A, Oguey-Araymon S, Beaumont M, Emady-Azar S, Ammon-Zufferey C, Monnard I, Pinaud S, Nielsen-Moennoz C, Bovetto L. Protein choices targeting thermogenesis and metabolism. Am J Clin Nutr. 2011 Mar;93(3):525-34.