Resting Metabolic Rate, Total Daily Energy Expenditure, and Metabolic Adaptation 6 Months and 24 Months After Bariatric Surgery

Abstract

ObjectiveLittle is known about long-term metabolic (energy expenditure) adaptation after bariatric surgery.MethodsResting metabolic rate under basal conditions (RMR), total daily energy expenditure (TDEE) and body composition were measured in 25 participants in the Longitudinal Assessment of Bariatric Surgery-2 (LABS-2).ResultsSix months after surgery, BMI (±SD) decreased (47 ± 6 to 37 ± 5 kg/m2), body fat from 48 ± 6 to 40 ± 6% fat and fat-free mass from 67 ± 9 to 60 ± 9 kg. In absolute terms RMR and TDEE both decreased significantly (1730 ± 278 vs. 1430 ± 200 and 2879 ± 544 vs. 2369 ± 304 kcal/day) and the achieved energy balance was −1293 ± 355 kcal/day. Sixteen of these participants underwent repeated measures at ~24 months; TDEE decreased 6 months postoperative (2957 ± 540 kcal/day to 2423 ± 324, P=0.0003), but at ~24 months, TDEE (2602 ± 471 kcal/day) was not significantly different compared to Month 6. The average negative energy balance from Baseline to Month 24 was −379 ± 131 kcal/day.ConclusionsRMR and TDEE fall precipitously in the first six months after bariatric surgery but these adaptive changes were no longer significant after two years.

Does adaptive thermogenesis occur after weight loss in adults? A systematic review

“…A significant value for AT was reported in 4 of the 6 studies (36,39). In two of these studies, AT only remained significant after 6 months, disappearing throughout time (34,37). AT values were slightly lower for those who had gastric band surgery when compared to other surgeries such as sleeve gastrectomy or Roux-en-Y gastric bypass (37).…”

“…A total of 5 studies reporting changes in TDEE were included in this review (34,(50)(51)(52)(53), with 2 RCTs (40%) and 3 prospective observational studies included (60%) (Table 3).…”

“…From those, 1 was related to a diet-only intervention (50), 2 to a diet-only vs. a combined diet and exercise intervention (51,52) and 2 to bariatric surgery (34,53).…”

“…Adaptive thermogenesis. AT was reported in 4 studies (34,(51)(52)(53) (50). Both studies that used weight reduction surgeries (34,53) reported a significant AT after 6 months, but not after 12 months (53) or 24 months (34).…”

Changes in resting metabolic rate and body composition due to intragastric balloon therapy

“…The mechanism of action likely involves stimulation of gastric mechanoreceptors triggering short-acting vagal signals to brain regions implicated in satiety [5]. Resting metabolic rate (RMR) is elevated among obese individuals; compared with healthyweight individuals it was shown to decrease with weight loss induced by dietary and/or physical activity interventions [6][7][8][9][10][11][12]. However, increases in RMR of individual patients were reported [13].…”