Topical Area: Energy and Macronutrient Metabolism
The purpose of this study was to examine the acute effects of consuming isocaloric, higher-protein breakfast shakes varying in protein source on appetite, satiety, and subsequent breakfast and lunch food intake in healthy adults.
Thirty-two adults (Age: 25±1y; BMI: 24.2±0.5 kg/m2) randomly consumed 250 kcal higher-protein breakfast shakes (24 g total protein; 17 g CHO; 9 g fat), varying only in protein source (whey protein isolate, WHEY; soy protein isolate, SOY; Micellar Casein, CAS; pea protein isolate, PEA; and milk protein isolate; MILK) for 3 days/shake. On day 4, the participants completed a 4-h testing day that included the consumption of the respective shake followed by blood sampling and questionnaires taken every 30 min to assess appetite and satiety. At the end of the testing day, an ad libitum lunch was provided. In addition, we sought to assess whether the study shakes consumed as breakfast preloads reduce food intake within the breakfast eating occasion. Thus, on day 5, the respective shake was consumed 30 min before an ad libitum breakfast.
Results : Postprandial differences in morning fullness and desire to eat were detected between protein shakes. Specifically, MILK led to greater 4-h fullness vs. WHEY, SOY, and PEA (all, P< 0.05) but not vs. CAS. CAS led to greater fullness vs. SOY (P< 0.05). In addition, MILK, CAS, and PEA led to greater decreases in 4-h desire to eat vs. SOY (all, P< 0.05). No differences in hunger, prospective food consumption, or food cravings were detected. At the subsequent lunch meal, the participants consumed on average 750 ± 70 kcal with no differences observed between shakes. Lastly, regardless of the protein source within the preloads, the participants consumed an additional +280 ± 50 kcal from other breakfast foods. Blood sampling analyses of metabolic analytes and appetite hormones are on-going.
Although protein source differences within isocaloric, higher-protein breakfast shakes influenced appetite responses throughout the morning, subsequent breakfast and lunch intake was not modified.
Funding Sources : Leprino Foods