Interrelationships among postprandial satiety, glucose and insulin responses and changes in subsequent food intake.

OBJECTIVE

The aim of this study was to investigate whether postprandial glucose and insulin responses were related to concurrent changes in satiety.

DESIGN

Thirty-eight common foods, grouped into six food categories, were tested in total. Each food category was fed to a separate group of subjects. A within-subjects repeated-measures design was used such that within each food category each subject consumed all of the test foods in random order.

SETTING

The study was conducted at the Human Nutrition Research Unit, Sydney University.

SUBJECTS

Separate groups of 11-13 healthy young subjects, who were unrestrained eaters, were recruited for each of the six food categories.

INTERVENTIONS

Isoenergetic 1000 kJ (240 kcal) portions of the test foods were fed to fasting subjects. Fingerprick blood samples and satiety ratings were obtained every 15 min over 120 min after which a standard meal was presented and ad libitum food intake was recorded. A glycaemic score, insulin index and satiety index score was calculated for each food by dividing the area under the 120 min response curve (AUC) for the test food by the AUC for white bread and multiplying by 100. Expressing the results of the test foods relative to those for white bread minimised the confounding influence of inherent differences between the subjects.

RESULTS

Among the 38 test foods, there were no significant relationships between satiety and plasma glucose or insulin responses. However, a negative correlation was found between insulin AUC responses and ad libitum food intake at 120 min which suggests that test foods producing a higher insulin response within 120 min were associated with less food intake and thus indirectly greater satiety. This result is consistent with previous findings that carbohydrate-rich foods are more satiating than fat-rich foods. Thus, total carbohydrate content appears to have been a stronger determinant of short-term satiety, in conjunction with the foods structural characteristics, than the foods glycaemic impact.

CONCLUSIONS

The total amount of carbohydrate consumed at a meal and subsequent insulinaemia may partly determine the degree of hunger arising within the next 2 h.