Abstract
Background: Several aspects of the postprandial effects of meals need further investigation. In particular, we were interested in focusing on whether the glycemic effect of meals is related to the serum concentration of hormones known to be involved in appetite regulation, and to hunger and food intake.
Objective/research questions: Will the intake of two lunch meals differing in the carbohydrate source, have different effects on a) the postprandial blood glucose concentration and b) serum levels of hormones related to appetite: insulin, ghrelin, leptin and growth hormone? Will possible differences in these variables be reflected in a) hunger during the next five hours and b) food intake at the next meal? Methods: Eleven overweight male adults were evaluated on two separate occasions in a cross over fashion. The subjects consumed at noon either a meal with an anticipated low or high glycemic effect (meal L and H respectively). The meals were similar in energy and fat content, taste and energy density, but had major differences in carbohydrate sources (lentils or potato as main sources of carbohydrate, respectively). Meal H and L differed also in protein, carbohydrate and fibre content. During five hours after the lunch meal, hunger, plasma blood glucose and serum hormone levels were measured. Five hours after lunch, the ad libitum food intake was determined at a single meal. Results: Glucose levels were remarkably stable after meal L and did not increase by more than 13 % to peak, whereas glucose levels after meal H increased by 52 % to peak and reached a nadir that was 8% lower than baseline values. There were significant differences after the two test meals in plasma ghrelin (H>L), growth hormone (H>L) and insulin concentration (H>L), but no differences in hunger or food intake were observed. Conclusion: Lunch meals with appreciably differing postprandial glycemic effects do not affect hunger or food intake in the next meal in overweight adults in this particular setting, in spite of differences in the serum level of appetite regulating hormones.