Energy Adaptations Persist 2 Years After Sleeve Gastrectomy and Gastric Bypass

Abstract

Non-surgical weight loss induces a greater than expected decrease in energy expenditure, a phenomenon known as 'metabolic adaptation'. The effects of different bariatric surgery procedures on metabolic adaptation are not yet known and may partially contribute to weight loss success. We compared resting energy expenditure (REE) in 35 subjects (nine males; age = 46 ± 11 years; BMI = 42.1 ± 6.5 kg/m(2)) undergoing gastric band, sleeve gastrectomy or Roux-en-Y gastric bypass (RYGB) up to 2 years after surgery. We found a greater than expected reduction of 130-300 kcal/day at 6 weeks after sleeve and bypass surgery which was not explained by changes in body composition; this change was not seen in the band group. The suppression in REE after sleeve and RYGB remained up to 2 years, even after weight loss had plateaued. Our findings suggest that energy adaptation is not a contributing mechanism to medium-term weight maintenance after sleeve and RYGB bariatric surgeries.

Blunting of adaptive thermogenesis as a potential additional mechanism to promote weight loss after gastric bypass

“…The lack of significant AT after LRYGB and LAGB in our participants is in agreement with previous findings that measured and predicted RMR were not different after bariatric surgery (16, 17) but conflicts with some other reports (5, 13). These inconsistencies may be at least partially ascribed to methodological differences across studies.…”

“…In contrast, Tam et al (13) reported significant AT in 11 patients after six months with LRYGB (262±62 kcal/d) but not in 8 patients with LAGB (148±85 kcal/d). As with the study by Knuth et al (5), Tam et al (13) also did not have complete post-operative data for all participants from which the initial RMR prediction equation was developed.…”

“…For instance, the 240-kcal/d greater decline in RMR observed following seven months of participation in “The Biggest Loser” competition in comparison to six months after laparoscopic Roux-en-Y gastric bypass (LRYGB) was nearly entirely accounted for by a larger AT (5). However, given the greater short-term and long-term weight loss and body composition improvements with LRYGB in comparison to laparoscopic adjustable gastric banding (LAGB) (12), a separate finding that AT was significantly larger six months after LRYGB than LAGB (13) obscures understanding of how AT might impact post-operative energy balance.…”

“…Since AT is quantified as the difference between the measured change in RMR and that which would be predicted from changes in metabolically active tissues, differences in the study populations from which the pre-weight loss RMR prediction equations were developed (e.g., both surgical and non-surgical weight loss-seekers (5) versus surgical patients only (13)) and the independent variables included in the RMR prediction equations (e.g., LBM, FM, and age (5) versus LBM, age, and sex (13)) may have influenced the AT calculations in these studies. Therefore, the objective of this study was to quantify AT following LRYGB and LAGB by comparing measured RMR to RMR predicted from LBM, FM, age, and sex before and after surgery.…”

Body Weight Reduction and Biochemical Parameters of the Patients After RYGB and SG Bariatric Procedures in 12-Month Observation

“…In the first postoperative period, the energy demand is increasing, body temperature is growing, hyperventilation occurs and the energy is crucial to sustain proper tissue perfusion, ATP and phosphocreatine levels, and thus proper wound healing. The study of Tam et al shows, however, that the resting energy expenditure (REE) adaptation mechanism after both types of surgeries (SG and RYGB) does not contribute to body mass reduction, because REE lowers by 130–300 kcal/day and these are long-term changes—measurable even 2 years after the surgery [25]. …”