Pouch size after gastric bypass does not correlate with weight loss outcome

A large gastric pouch is a classic explanation for weight loss problems after gastric bypass. However, several reports have emphasized the role of others, essentially behavorial, factors. We reviewed the outcomes of 151 patients who were operated on over a period of nearly 2 years. 132 patients who had not been reoperated on were assessed between June and September 2009. A barium swallow was available to assess the gastric pouch volume which was determined by the radiologist. %EWL was compared to the pouch volume using ANOVA test. Pouch volumes were compared using t test. The gastric pouch was dilated when >50 ml and failure to lose enough weight was defined by a %EWL<50%. 107 patients (81%) had a complete follow up of 35.7 ± 5.8 months. Mean pouch volume was 68 ± 4.5 ml with a %EWL of 68 ± 26.1%. 59 patients had a large pouch with a weight loss similar to those with a normally sized pouch (68 ± 3.6 vs 66 ± 3.6%EWL). 25 patients (23.3%) had weight loss failure with a similar pouch volume. No correlation was found between the %EWL and the pouch volume. Pouch size probably plays a role in the weight loss process of RYGB. However, 3 years later, pouch volume does not appear to be the most important factor. Behavorial factors such as recurrent eating disorders and failure to adapt to the changes induced by the surgery may explain at least in part weight loss failure.