A rice diet is associated with less fat synthesis/accumulation than a bread diet before exercise therapy

For effective exercise therapy after waking up, we focused on the staple food in diet therapy, and compared rice and bread diets. The subjects were 10 healthy college male students. After fasting for 12 h or more from the previous day, the subjects had breakfast consisting of rice (protein, 6.3 g; fat, 0.9 g: CHO, 79.3 g; energy, 368 kcal) or bread (protein, 15.7 g; fat, 5.8 g; CHO, 79.2 g; and energy, 450 kcal) containing the same amount of carbohydrates and the same side dishes (protein, 7.0 g; fat, 9.5 g; CHO, 21.3 g; energy, 199 kcal) in the morning 30 min before the initiation of exercise on a bicycle ergometer at an intensity of about 50% VO2max for 60 min. Measurements of the heart rate and expired gas were initiated 15 min before the start of exercise and continued until 10 min after exercise. Blood was collected before the meal, immediately before and 15, 30, and 45 min after the initiation of exercise, and immediately, 15, and 30 min after its termination. After breakfast containing carbohydrates, decreases were observed in the levels of free fatty acid and noradrenalin. Blood insulin (mealxtime, p<0.05 ANOVA) and triglyceride (meal x time, p<0.01, ANOVA) changed at higher levels in the bread diet than in the rice diet. Blood triglyceride is a resource of fat synthesis/accumulation, and insulin promotes its action. Therefore, the bread diet may promote fat synthesis/accumulation compared with the rice diet.