Changes In Intestinal Bacteria After Quitting Smoking Cause Weight Gain

Weight gain after quitting smoking is not due to increased caloric intake, according to new Swiss research, but to a shift in the microbial composition of the intestines. The small study involved 20 participants – five nonsmokers, five smokers and ten who had quit smoking a week before. An analysis of the genetic composition of fecal material showed that the intestinal microbial content of those who had quit smoking shifted dramatically. They gained an average of 2.2 kilos, though their eating and drinking habits stayed the same. The researchers suggested that the changes in the bacteria in the intestines after giving up smoking provided the body with more calories, resulting in weight gain.