A protein-rich beverage consumed as a breakfast meal leads to weaker appetitive and dietary responses v. a protein-rich solid breakfast meal in adolescents

The purpose of the present study was to determine whether a protein-rich beverage leads to a differential response in appetite, satiety and subsequent energy intake compared with an energy-and macronutrient-matched solid version in young people. A total of fifteen adolescents (eight girls and seven boys; age 14 (SEM 1) years, BMI percentile 79 (SEM 4) %) randomly completed two testing days that included protein-rich (PR) breakfast meals (38% of energy as protein, 48 (SEM 2) g/meal) provided as a solid (S) or beverage (B). Breakfast was 24% of estimated daily energy needs (2146 (SEM 96) kJ/meal). Perceived appetite and satiety responses were collected over 5 h followed by an ad libitum lunch buffet. The PR-S meal led to greater reductions in 4 h postprandial appetite (-6221 (SEM 1171) mm x 240 min) v. the PR-B meal (-3570 (SEM 957) mm x 240 min; P<0.05). When examining the data according to hourly responses, the PR-S meal led to greater reductions in appetite during postprandial hours 2, 3 and 4 v. the PR-B meal (all comparisons, P<0.05). No differences in postprandial hourly or total (4h) fullness were observed following the PR-S v. PR-B meals. The PR-S meal led to approximately 480 kJ less energy consumed at the ad libitum lunch buffet (1418 (SEM 222) kJ) v. the PR-B meal (1900 (SEM 326) kJ; P<0.05). These data indicate that, although the food form of the PR breakfast meals had little, if any, effect on satiety, the appetitive responses were diminished and the subsequent food intake was greater when protein was consumed as a beverage v. a solid meal.