Effects of food form and portion size on postprandial appetite, ghrelin, and energy expenditure in healthy, older adults

Abstract

Objective: To examine the independent and combined influences of food form and portion size on appetite and metabolic responses. Methods: 43 older men and women (age: 72 ± 1 y; BMI: 25.6 ± 0.3 kg/m2) consumed, on 2 separate days, preloads in solid (S) vs. beverage (B) form as either 12.5% (264 ± 8 kcal) or 25% (533 ± 14 kcal) of estimated daily energy need. Postprandial (PP) appetite (hunger, fullness, desire to eat), plasma ghrelin concentration, and energy expenditure (EE) were measured over 4 h. Results: Main effects of food form (p<0.05) and portion size (p<0.05) were observed for appetite; PP hunger and desire to eat area under the curve (AUC) values were higher and fullness AUC values were lower for B vs. S and between 12.5% vs. 25%. Post‐hoc analyses revealed no difference in appetite between the S‐12.5% vs. S‐25%. However, B‐12.5% led to higher hunger and desire to eat and lower fullness AUC values vs. the B‐25% (p<0.05). No difference in 4‐h ghrelin was observed between S vs. B and 12.5% vs. 25%. Concerning PPEE, the B treatment led to lower overall PPEE vs. S when consuming 25% (p<0.01) but not 12.5%. Conclusion: Several key parameters of appetite appear to be independently and additively influenced by food form and portion size with particular insensitivity to lower energy beverages in healthy, older adults.Support: NIH R01 AG021911; The Solae Company; IBRC, Purdue University