Bethesda, Md. (July 27, 2011)Roux-en-Y gastric bypass, the most common type of bariatric surgery in the United States, is currently considered the most effective therapy for morbid obesity. Patients who undergo this procedure, in which the stomach is reduced to a small pouch and connected to the middle of the small intestine, often lose massive amounts of weight. However, the reasons behind this surgery's success have been unclear. Shedding more light on why this procedure prompts such dramatic weight loss, a team of researchers has found, in a study using both humans and rats, that Roux-en-Y appears to lead patients to significantly reduce their intake of dietary fat. This effect, which was present for both solid and liquid dietary fat, lingered for up to 200 days after surgery in the animals. Further experiments suggest that this fat avoidance is triggered through digestive consequences, rather than just altered taste, and may be the result of an excess of hormones previously linked to food avoidance.
The study is entitled "Gastric Bypass Reduces Fat Intake and Preference." It appears in the Articles in PresS section of the American Journal of Physiology Regulatory, Integrative, and Comparative Physiology, published by the American Physiological Society.
The researchers used data from a study in obese people comparing gastric bypass to vertical-banded gastroplasty. At 1 and 6 years after surgery, these patients were asked to fill out questionnaires that included a series of questions to determine whether they avoided certain foods.
The researchers also performed either Roux-en-Y gastric bypass or sham operations on rats. At time points ranging from 10 to 200 days after surgery, these animals were subjected to various food preference experiments.
In one experiment, the rats were offered either high- or low-fat chow, with the researchers comparing the animals' intake of both foods before
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American Physiological Society