Does intestinal absorption participate in the ponderostat?

Body weight regulation is known to achieve energy balance through several responses: appetite, satiety, thermogenesis, feeding behavior. Absorption efficiency might be, also, another response. In this paper, we hypothesized that the intestinal absorption efficiency of the rat might be lowered in response to a high energy content of the diet. Thirty-one rats were assigned to a specific diet (restricted, control, and cafeteria) during three weeks. Rats' body mass, BMI, and body fat were measured and absorption efficiency was calculated through the ratio of energy ingested/energy defecated. Intestinal histology was examined post-mortem. Absorption efficiency was not lower in cafeteria groups but was higher than in control and restricted rats. No histological difference was seen after the various diets. Such results indicate that intestinal absorption is working at full efficiency whatever the diet, and is not a regulatory response contributing to the ponderostat.