Meal-frequency effects on plasma hormone concentrations and cholesterol synthesis in humans

To examine meal-frequency effects on circulating hormone concentrations and cholesterol synthesis, male subjects consumed liquid diets given as either six evenly spaced (ES) or three diurnal (DI) meals over 3 d. Deuterium oxide was given on day 2 and blood sampled every 4 h over days 2 and 3 to measure plasma cholesterol, glucose, insulin, and glucose-dependent insulinotropic polypeptide (GIP) concentrations and cholesterol synthesis. Cholesterol synthesis was determined from deuterium incorporation into plasma free cholesterol by using constrained and unconstrained curve-fit models. Plasma total cholesterol concentrations decreased in both ES and DI groups (P < 0.05). The ES group had lower insulin (P < 0.05) and GIP (P < 0.001) concentrations compared with the DI group. Cholesterol synthesis was reduced (P < 0.01) in the ES vs the DI group when determined by using constrained (0.050 +/- 0.002 vs 0.075 +/- 0.005 pools/d, respectively) and unconstrained (0.072 +/- 0.005 vs 0.119 +/- 0.011 pools/d, respectively) models. These data suggest meal frequency-dependent control of cholesterogenesis via hormonally mediated mechanisms.