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

Background: 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.

Methods: 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.

Results: 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.

Conclusion: 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.