Water with food intake does not influence caloric intake after gastric bypass (GBP): a cross-over trial

Bariatric patients seeking information meet very different recommendations on postoperative diet and eating behaviour. A reason for variability may be lack of hard evidence. A national survey on current dietary advice was conducted to serve as background for the present study on how drinking during a meal influenced caloric consumption.

A standardised questionnaire was sent to all units in the Scandinavian Obesity surgery registry (SOReg) in order to obtain information regarding current diet advice after gastric bypass. Twenty-eight patients, 14 in each group, were studied either 2 months or 1 year after a standard gastric bypass (GBP). A standardised lunch was served on two separate days with or without water in randomised order. Meal and water weights were measured before and after. Hunger/satiety scores were obtained using visual analogue scales.

Response rate for surgeons was low, for dieticians 75 %. No clear consensus for liquid intake during meals was found; few surgeons advised patients whether or not to drink with meals. All patients ate to full satiety. Two months post-GBP, 7/14 patients consumed more solid food when allowed drinking water; the increase in caloric consumption was not significant. One year post-GBP, 5/14 patients consumed more solid food when allowed drinking water, the difference not reaching statistical significance.

Our study does not indicate that patients should refrain from drinking during meals the first year after a GBP, at least not from a caloric intake point of view.