Effect of dietary fibre on postprandial thermogenesis

The effect of fibre on postprandial thermogenesis was evaluated in seven healthy males (age 29.6 +/- 3.6 years, BMI 24.6 +/- 0.6 kg/m2) after they had ingested three isocaloric meals with different fibre contents: low fibre (Lfb) containing 8 g. dietary fibre; glucomannan (Glc), which was Lfb supplemented with 6 g glucomannan, a pectin-like fibre; and high fibre (Hfb) containing 26 g dietary fibre. Postprandial thermogenesis, evaluated for 6 h after the ingestion of food, was higher after the Lfb (82.3 +/- 5.4 kcal) than after the Hfb and Glc meals (69.4 +/- 6.8 and 61.4 +/- 8.4 kcal, respectively). Glucose and insulin responses were depressed over the first 2 h after the Hfb and Glc meals as compared to the Lfb meal. However, these differences disappeared when the whole 6 h postprandial period was considered. No major effects of the different fibre contents of the meals on postprandial triglyceride and FFA levels were detected. These results demonstrate that the fibre content of meals, besides the well known effect on energy intake, may also affect energy expenditure.