Cognitive factors and anticipation are known to influence food intake. The current study examined the effect of anticipation and actual consumption of food on hormone (ghrelin, cortisol, and insulin) and glucose levels, appetite and ad libitum intake, to assess whether changes in hormone levels might explain the predicted differences in subsequent food intake.
Design and Methods
During four breakfast sessions, participants consumed a yogurt preload that was either low caloric (LC: 180 kcal/300 g) or high caloric (HC: 530 kcal/300 g) and was provided with either consistent or inconsistent calorie information (i.e., stating the caloric content of the preload was low or high). Appetite ratings and hormone and glucose levels were measured at baseline (t = 0), after providing the calorie information about the preload (t = 20), after consumption of the preload (t = 40), and just before ad libitum intake (t = 60).
Ad libitum intake was lower after HC preloads (as compared to LC preloads; P < 0.01). Intake after LC preloads was higher when provided with (consistent) LC information (467±254 kcal) as compared to (inconsistent) HC information (346±210 kcal), but intake after the HC preloads did not depend on the information provided (LC information: 290±178 kcal, HC information: 333±179 kcal; caloric load*information P = 0.03). Hormone levels did not respond in an anticipatory manner, and the post-prandial responses depended on actual calories consumed.
These results suggest that both cognitive and physiological information determine food intake. When actual caloric intake was sufficient to produce physiological satiety, cognitive factors played no role; however, when physiological satiety was limited, cognitively induced satiety reduced intake to comparable levels.