Objective To investigate how
weight loss by different diets impacts postprandial levels of
glucagon-like peptide 1 (GLP-1),
glucose-dependent insulinotropic
polypeptide (GIP) and
glucagon. Methods In this single-centre, parallel group 2-year trial, 70 healthy postmenopausal obese women were randomised to the
Paleolithic diet or a healthy control diet based on Nordic Nutrition Recommendations. Both diets were without calorie restriction. The primary outcome was the change in fat mass. Here, secondary analyses on
GLP-1, GIP and
glucagon measured during an OGTT are described. Results In the
Paleolithic diet group, mean
weight loss compared to baseline was 11% at 6 months and 10% at 24 months. In the control diet group, mean
weight loss was 6% after 6 and 24 months (P = 0.0001 and P = 0.049 for the comparison between groups at 6 and 24 months respectively). Compared to baseline, the mean incremental area under the curve (iAUC) for
GLP-1 increased by 34 and 45% after 6 and 24 months in the
Paleolithic diet group and increased by 59% after 24 months in the control diet group. The mean iAUC for GIP increased only in the
Paleolithic diet group. The area under the curve (AUC) for
glucagon increased during the first 6 months in both groups. The fasting
glucagon increase correlated with the β-hydroxybutyrate increase. Conclusions
Weight loss caused an increase in postprandial
GLP-1 levels and a further rise occurred during weight maintenance. Postprandial GIP levels increased only after the
Paleolithic diet. Reduced postprandial
glucagon suppression may be caused by a catabolic state.