Because weight loss is common in colonic Crohn's disease and is poorly correlated with disease activity, we analyzed food intake in 63 patients without malabsorption, 30 patients with weight loss (9.2 +/- 4.2 kg), and 33 patients without weight loss. Energy and protein intakes were lower in patients with weight loss than in those with stable weight (P < 0.01). In the former group, food restrictions were more numerous (P < 0.01) and visual analog scales showed less hunger, decreased appetite, and fewer sensations of pleasure related to eating, as compared with the other group (P < 0.01). Food intake reduction was also related to depressive mood and medical advice. However, there was no difference between groups in fecal energy wasting and resting energy expenditure. Weight loss in Crohn's disease may be due to a decrease in food intake rather than to an increase in energy cost of the disease. Thus, focus of attention on the diet is crucial to prevent malnutrition.