773-P: The Study of Metabolic Improvement by Nutritional Intervention Controlling Endogenous GIP (Mini Egg Study): A Randomized, Double-Blinded, Crossover Study

Objective: Given the major role of glucose-dependent insulinotropic polypeptide (GIP) in the regulation of adiposity, this study examined the effects induced by a diet based on the Japanese tradition (SMART WASHOKU) on the visceral fat area (VFA) and GIP secretions.

Research Design and Methods: Overweight/obese men (n=21; mean age: 41 ± 9 y; mean BMI: 25.2 ± 2.0 kg/m2) without diabetes were placed on either a SMART WASHOKU (protein/fat=1.0, fiber/carb ratio≥0.063, and omega-3 PUFA/fat ratio ≥0.054) or isocaloric control meal for two weeks, in a randomized, double-blind, cross-over setup with a four-week washout period. For the meal tolerance test, blood samples were collected at 0, 30, 60, 120, 180, and 240 minutes post-meal, followed by measuring blood glucose, insulin, GIP, and glucagon-like peptide-1 (GLP-1) levels.

Results: Relative to a control meal, SMART WASHOKU meal yielded significantly lower plasma postprandial GIP concentrations (AUC: 700.0 ± 208.0 vs. 1117.0 ± 351.4, P < 0.05); however, between meals, there was no significant difference in the levels of GLP-1, PYY, and ghrelin. Relative to control meal, a SMART WASHOKU intervention produced a modest but significant reduction of VFA in our participants (-3.4 ± 12.3 vs. -13.0 ± 9.3 cm2, P < 0.05). Compared with the control meal, SMART WASHOKU meal did not modify the concentrations of AST, ALT, GGT, and hs-CRP; however, we did observe a significantly reduced in the levels of LDL-cholesterol, triglyceride, and HbA1c.

Conclusions: Based on our findings, we conclude that in overweight/obese men, a SMART WASHOKU meal would be helpful in decreasing VFA and improving metabolic parameters, possibly via suppressing GIP secretion.