Abstract
BACKGROUNDRoux-en-Y gastric bypass (RYGB) decreases energy intake and is, therefore, an effective treatment of obesity. The behavioral bases of the decreased calorie intake remain to be elucidated. We applied the methodology of microstructural analysis of meal intake to establish the behavioral features of ingestion in an effort to discern the various controls of feeding as a function of RYGB.METHODSThe ingestive microstructure of a standardized liquid meal in a cohort of 11 RYGB patients, in 10 patients with obesity, and in 10 healthy-weight adults was prospectively assessed from baseline to 1 year with a custom-designed drinkometer. Statistics were performed on log-transformed ratios of change from baseline so that each participant served as their own control, and proportional increases and decreases were numerically symmetrical. Data-driven (3 seconds) and additional burst pause criteria (1 and 5 seconds) were used.RESULTSAt baseline, the mean meal size (909.2 versus 557.6 kCal), burst size (28.8 versus 17.6 mL), and meal duration (433 versus 381 seconds) differed between RYGB patients and healthy-weight controls, whereas suck volume (5.2 versus 4.6 mL) and number of bursts (19.7 versus 20.1) were comparable. At 1 year, the ingestive differences between the RYGB and healthy-weight groups disappeared due to significantly decreased burst size (P = 0.008) and meal duration (P = 0.034) after RYGB. The first-minute intake also decreased after RYGB (P = 0.022).CONCLUSIONRYGB induced dynamic changes in ingestive behavior over the first postoperative year. While the eating pattern of controls remained stable, RYGB patients reduced their meal size by decreasing burst size and meal duration, suggesting that increased postingestive sensibility may mediate postbariatric ingestive behavior.TRIAL REGISTRATIONNCT03747445; https://clinicaltrials.gov/ct2/show/NCT03747445.FUNDINGThis work was supported by the University of Zurich, the Swiss National Fund (32003B_182309), and the Olga Mayenfisch Foundation. Bálint File was supported by the Hungarian Brain Research Program Grant (grant no. 2017-1.2.1-NKP-2017-00002).
Highlights
The rising prevalence of obesity worldwide emphasizes the need for improved strategies of prevention and control [1]
Potential underlying mechanisms of Roux-en-Y gastric bypass (RYGB) include amplified postprandial gut-hormone response [7, 8], changes in vagal nerve signaling mediated by intestinal contents and/or gastrointestinal distention [9], modifications in composition and metabolic activity of gut microbiota [10], and an altered bile acid physiology and signaling through FXR and TGR5 receptors [11]
With few exceptions, most of these findings rely on indirect measures of food intake — e.g., interviews or questionnaires [15, 16] — whereas direct examinations using a cafeteria setting failed to replicate shifts in food preference in humans after RYGB [17, 18]
Summary
The rising prevalence of obesity worldwide emphasizes the need for improved strategies of prevention and control [1]. Roux-en-Y gastric bypass (RYGB) is one of the most often performed procedures worldwide [3], but it is the most intensively investigated procedure to decipher the physiological mechanisms underlying bariatric surgery [4,5,6]. Since self-reported changes may not correlate with measured ingestive behaviors, patients after bariatric surgery may consume less of what they were eating before [19]. The role of RYGB on food choices in humans remains to be investigated with more direct measures of eating behavior. Roux-en-Y gastric bypass (RYGB) decreases energy intake and is, an effective treatment of obesity.
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