Influence of substrate oxidation on the reward system, no role of dietary fibre.

It has been suggested that a high intake of dietary fibre helps regulate energy intake and satiety. The present study aimed to examine whether dietary fibre influenced the liking and wanting components of the food reward system, the metabolic state or subsequent intake. Five sessions involving 32 normal-weight subjects (16 men and 16 women, 30.6 ± 7.6 year) were held. The sessions differed in the composition of the bread eaten during breakfasts (dietary fibre content varied from 2.4 to 12.8 g/100 g). Several factors such as the palatability, weight, volume, energy content and macronutrient composition of the breakfasts were adjusted. Energy expenditure, the respiratory quotient (R), olfactory liking for four foods, wanting for six other foods, and hunger sensations were evaluated before and after the breakfast, as well as before a morning snack. The results showed no significant differences after ingestion of the various breads. Interestingly, R correlated with olfactory liking and with wanting, which highlights in an original manner the influence of the metabolic state on hedonic sensations for food. In conclusion, dietary fibre was found to have no effect on olfactory liking and wanting, and had no detectable effect on satiety sensations or on subsequent energy intake.