Controversy exists over the contribution of dietary fiber and large bowel fermentation to human energy balance. It has been suggested that large bowel energy absorption, in the form of short-chain fatty acids, can be predicted from in vitro fermentation of human ileal digesta. Because it is difficult to obtain ileal digesta from humans with a functional large bowel to validate this approach, four normal pigs and four pigs fitted with a simple T-cannula at the distal ileum were fed a basal diet supplemented with 0, 5, 10 or 15 g pea fiber per 100 g basal diet in two parallel experiments (Latin-square design). Energy contents of diets, urine, ileal digesta and feces were determined by bomb calorimetry. Apparent total tract energy digestibility did not differ (P > 0.05) between normal and cannulated pigs. Apparent energy digestibility at the ileum decreased with increasing pea fiber intake (P < 0.05). The difference between ileal and fecal gross energy excretions in cannulated pigs was defined as large bowel energy absorption. Aliquots (0.2 g) of freeze-dried ileal digesta were fermented in vitro for 24 h with human fecal inoculum from three donors. In vitro short-chain fatty acid production was correlated with large bowel energy absorption (r = 0.90, P < 0.0001). The metabolizable energy content of pea fiber was determined to be 9.2 kJ/g pea fiber (r = 0.90, P < 0.0001) by regressing metabolizable energy retention against pea fiber intake. The integrated ileostomy-in vitro fermentation model seems to provide accurate estimates of large bowel energy absorption.