Perceived thickness and creaminess modulates the short-term satiating effects of high-protein drinks

Previous research suggests that increasing beverage protein content enhances subsequent satiety, but whether this effect is entirely attributable to post-ingestive effects of protein or is partly caused by the distinct sensory characteristics imparted by the presence of protein remains unclear. To try and discriminate nutritive from sensory effects of added protein, we contrasted effects of three higher-energy (about 1·2 MJ) and one lower-energy (LE: 0·35 MJ) drink preloads on subsequent appetite and lunch intake. Two higher-energy drinks had 44% of energy from protein, one with the sensory characteristics of a juice drink (HP2, low-sensory protein) and the second a thicker and creamier (HPþ, high-sensory protein) drink. The high-carbohydrate preload (HCþ, high-sensory carbohydrate) was matched for thickness and creaminess to the HPþ drink. Participants (healthy male volunteers, n 26) consumed significantly less at lunch after the HPþ(566 g) and HCþ(572 g) than after HP2 (623 g) and LE (668 g) drinks, although the compensation for drink energy accounted for only 50% of extra energy at best. Appetite ratings indicated that participants felt significantly less hungry and more full immediately before lunch in HPþ and HCþ groups compared with LE, with HP2 being intermediate. The finding that protein generated stronger satiety in the context of a thicker creamier drink (HPþ but not HP2) and that an isoenergetic carbohydrate drink (HCþ), matched in thickness and creaminess to the HPþ drink, generated the same pattern of satiety as HPþ, both suggest an important role for these sensory cues in the development of protein-based satiety.