Soybean snack does not inhibit post‐prandial fat oxidation

Abstract

Soybean (Soy) intake after overnight fasting increased post‐prandial energy expenditure (EE) compared to wheat intake. We assessed the metabolic consequences of Soy or wheat snacks consumption. Ten healthy male volunteers (29.2 yrs, BMI= 23.7) attend 3 sessions (non‐snack: Non, Soy, Wheat) in a random order with at least one week of wash out period. Soy and Wheat trials were blinded. In each testing day, subjects ate regular breakfast at 0730 and lunch at 1200, and test snack (17 kJ/kg) at 1515 in Soy and Wheat sessions. Expired gas and blood samples were collected every an hour from 1100 until 2115 to determine EE and substrate oxidation (OX) and glucose, insulin and lipid profiles in the blood. Plasma glucose and serum insulin levels were markedly lower in Soy than in Wheat (P<0.05). And those levels in Soy were only slightly higher compared to Non (P<0.05). EE after snack was not different between three sessions. However, change in fat OX was higher and carbohydrate OX was lower in Soy and Non than in Wheat (P<0.05). In addition, serum triglyceride level was higher in Soy than in Wheat and Non (P<0.05). Serum free fatty acid level was higher in Non than in Soy, and further lower in Wheat (P<0.05). These findings suggested that soybean snack does not inhibit acceleration of post‐prandial fat OX, but wheat snack does, possibly by insulin's action of fat storage.