You often hear about how important protein is in terms of enhancing protein synthesis and lean body mass gains. What you may not hear about or appreciate regarding protein is that it is superior to carbohydrate and fat in promoting satiety. In other words, eating protein makes you feel more full than eating carbohydrate or fat. A recent study looked further at the effects of protein source and timing on measures of satiety in a series of experiments. Subjects were provided standardized preloads containing either water, sugar or 3 types of protein: egg albumin, whey, or soy. One or two hours after ingestion of these preloads, subjects were provided with a pizza meal and asked to eat until they were comfortably full. The experiments were also performed at different times of the day to see how this affected the responses. Pizza intake was consistently lower after whey protein compared to carbohydrate and other sources of protein, indicating whey-promoted satiety to the greatest extent. Surprisingly, egg protein did not have this same effect, in fact, it tended to promote greater food intake compared to control. The reason for the satiety promoting effect of whey may be due to the rapid absorption and increase in circulating amino acids, which may affect brain levels of hormones that control appetite. This study shows another benefit of whey beyond promoting protein synthesis. For those trying to lose weight, whey protein stimulates protein synthesis, increases thermogenesis, and according to this study reduces food intake. Sounds like the perfect food for fat loss.

Anderson GH, Tecimer SN, Shah D, Zafar TA. Protein source, quantity, and time of consumption determine the effect of proteins on short-term food intake in young men. J Nutr. 2004 Nov;134(11):3011-5.