Background: Little is known about eating behaviour and meal pattern subsequent to Roux-en-Y gastric bypass (RYGB), knowledge important for the nutritional care process. The objective of the study was to obtain basic information of how meal size, eating rate, meal frequency and eating behaviour change upon the RYGB surgery. Materials and methods: Voluntary chosen meal size and eating rate were measured in a longitudinal, within subject, cohort study of 43 patients, 31 women and 12 men, age 42.6 (s.d. 9.7) years, body mass index (BMI) 44.5 (4.9) kg m À2 . Thirty-one non-obese subjects, 37.8 (13.6) years, BMI 23.7 (2.7) kg m À2 served as a reference group. All subjects completed a meal pattern questionnaire and the Three-Factor Eating Questionnaire (TFEQ-R21). Results: Six weeks postoperatively meal size was 42% of the preoperative meal size, (Po0.001). After 1 and 2 years, meal size increased but was still lower than preoperative size 57% (Po0.001) and 66% (Po0.001), respectively. Mean meal duration was constant before and after surgery. Mean eating rate measured as amount consumed food per minute was 45% of preoperative eating rate 6 weeks postoperatively (Po0.001). After 1 and 2 years, eating rate increased to 65% (Po0.001) and 72% (Po0.001), respectively, of preoperative rate. Number of meals per day increased from 4.9 (95% confidence interval, 4.4,5.4) preoperatively to 6 weeks: 5.2 (4.9,5.6), (not significant), 1 year 5.8 (5.5,6.1), (P ¼ 0.003), and 2 years 5.4 (5.1,5.7), (not significant). Emotional and uncontrolled eating were significantly decreased postoperatively, (both Po0.001 at all-time points), while cognitive restraint was only transiently increased 6 weeks postoperatively (P ¼ 0.011). Conclusions: Subsequent to RYGB, patients display markedly changed eating behaviour and meal patterns, which may lead to sustained weight loss.
