Satiating properties of meat-preparations : role of protein content and energy density

Objective: To investigate the effects of three beef-based preparations (roast-beef, boiled beef, canned beef in jelly) on satiety and eating behavior. Methods: Ten male and ten female healthy volunteers (normal weight for height) were recruited. Three different studies were conducted, all with a within-subjects design. In Study 1, the effect of the beef-preparations on the specific satiety was evaluated by ad libitum consumption. In Study 2, the effect of the beef-preparations, proposed as a first course (preload) of a complete meal, on the total energy intake was explored. Subjects were asked to eat the beef-preloads (260g for women; 400g for men) in full, and then to consume as much as they wanted of a test meal. A no-load condition (ad libitum test meal consumption without any meat-preload) was included. In Study 3, the contribution of three different amounts of canned beef, served with a fixed amount of salad, on the desire to eat and satiety sensations over time was evaluated. Results: In Study 1, energy, weight and protein intakes were significantly affected by the type of beef-preparation, but not by pleasantness. In fact, specific satiety was reached with comparable amount of boiled meat and roast-beef, whilst canned meat was eaten in a higher amount, despite a lower rating of pleasantness. In Study 2, total energy was independent of the type of beef-preparation and was always lower than in the no-load condition; on the contrary, weight intake was similar in all conditions. From Study 3, a significant effect of time and low-energy protein food portion/time interaction on satiety ratings was observed. Conclusion: The satiating properties of the beef-preparations did not depend strictly on protein content; on the contrary, physical characteristics and, mainly, energy density seemed the most effective determinants. However, small portions of low-energy dense-protein foods seemed to be useful in modulating satiety sensations. On the whole, our results suggest that high protein intakes are not necessarily the only way to control food intake.