Comment In spite of symptoms such as anorexia, nausea, and vomiting and advice to avoid fatty foods, 31% of our patients were overweight before operation, confirming the preoperative findings of others.2 3 Our study showed that a significant weight gain occurred after cholecystectomy, with men gaining a mean of 4-6% of preoperative body weight and women 3 3% after six months. When patients who either lost weight or remained the same weight were excluded the mean percentage weight gain rose to 6°’ and 6 6%, respectively. We presume that this weight gain was caused by a reintroduction of fats into the diet, although a metabolic cause cannot be completely excluded. As one third of our patients were already overweight, any further weight gain could be considered to be detrimental to their long term health. We now routinely inform patients undergoing cholecystectomy that they are likely to gain weight after operation and advise them accordingly.