Breakfasts with different fiber and macronutrient contents do not differentially affect timing, size or microstructure of the subsequent lunch.

The effects of four equienergetic breakfasts with varying fiber and macronutrient contents on hunger and satiety ratings, on subsequent lunch intake, and on postprandial carbohydrate and fat metabolism were investigated in normal weight male subjects in two experiments, in which lunch was offered at a predetermined time (Experiment 1) or in which the subjects were free to choose when to eat lunch (Experiment 2). Consumption of either a commercially available high fiber cereal (HFC, 10% fiber), a medium fiber cereal (MFC, 7% fiber), a low fiber cereal (LFC, 3% fiber), or a standard continental breakfast (0% fiber) on nonconsecutive days did not differentially affect hunger and satiety ratings, the size or microstructure of the subsequent lunch, and the breakfast to lunch intermeal interval (in Experiment 2). Plasma concentrations of glucose, lactate, and insulin increased more after the LFC breakfast than after the other breakfast varieties. A reactive postprandial hypoglycaemia occurred after the LFC breakfast, shortly before lunch. The plasma concentrations of fat metabolites (triglycerides, free fatty acids, beta-hydroxybutyrate) and of glucagon were not differentially affected by the breakfast varieties. The results are consistent with the assumption that energy content of a meal is the major determinant of subsequent energy intake in man and the fiber content and macronutrient composition have only a modulating effect.