Preoperative high respiratory quotient correlates with lower weight loss after bariatric surgery
- 4 Downloads
The respiratory coefficient (RQ), as determined by indirect calorimetry (IC), classifies diet as being carbohydrate rich (RQ = 0.7–0.8), fat rich (RQ = 0.9–1.0), or overfeeding (RQ > 1). We hypothesized that preoperative RQ may be associated with weight-loss outcomes after bariatric surgery.
From 2016 to 2018, 137 obese patients were enrolled in a Bariatric Registry and underwent dietary and behavioral counseling, followed by preoperative IC. Resting energy expenditure (REE) and RQ of all patients was measured. Patients were classified as over-feeders (OF; 42, 31%) with RQ > 1 or non-over-feeders (NOF; 95, 69%) with RQ < 1. At baseline, there was no difference between groups in gender [female: 105 (76.6%), male: 32 (23.4%)], body mass index (BMI; OF: 46.8 ± 7.8 vs. NOF: 44.8 ± 7.4 kg/m2, p = 0.40), or baseline REE (OF: 1897 ± 622 vs. NOF: 1874 ± 579, p = 0.74), although OF were younger [mean age (OF: 47.1 ± 13.0 years vs. NOF: 43.1 ± 13.4; p = 0.009). At 6-month follow-up 94 patients [53.28%; OF: 35 (83%) vs. NOF: 59 (62%), p = 0.016] were seen and 48 [35.03%; OF: 23 (55%) vs. NOF: 25 (59%), p = 0.001] at 12-month follow-up. On preoperative psychological assessment, OF had a significantly higher rate of childhood neglect (OF: 28 (47.46%) vs. NOF: 40 (28.99%); p = 0.01).
At 1 year postoperatively, the OF had a significantly higher BMI (OF: 34.3 ± 6.5 vs. NOF: 29.3 ± 5.1 kg/m2, p = 0.009). Differences in weight were not significant at 6-month (OF: 36.0 ± 6.5 vs. NOF: 33.5 ± 5.9 kg/m2, p = 0.07). There was no difference between type of operation and RQ group (RYGB; OF: 55 (75%) vs. NOF: 18 (25%) and SG; OF: 40 (62%) vs. NOF: 24 (38%), p = 0.14), nor in BMI loss after operation.
Evidence of overfeeding in the preoperative period prior to bariatric surgery is associated with higher resultant BMI at 1 year. Calculation of the RQ with IC has prognostic significance in bariatric surgery, and calculation of REE based on assumed normal RQ potentiates error. It is unclear if overfeeding is purely behavioral or secondary to potentially reversible metabolic etiology.
KeywordsBariatric surgery Bypass Sleeve Respiratory quotient
Compliance with ethical standards
Armando Rosales, Enrique Elli, Scott Lynch, Gretchen Ames, Mauricia Buchanan, and Steven P Bowers have no conflicts of interest or financial ties to disclose.
- 2.Rosales-Velderrain A, Goldberg RF, Ames GE, Stone RL, Lynch SA, Bowers SP (2014) Hypometabolizers: characteristics of obese patients with abnormally low resting energy expenditure. Am Surg 80:290–294Google Scholar
- 8.Seidell JC, Muller DC, Sorkin JD, Andres R (1992) Fasting respiratory exchange ratio and resting metabolic rate as predictors of weight gain: the Baltimore Longitudinal Study on Aging. Int J Obes Relat Metab Disord 16:667–674Google Scholar
- 10.Zurlo F, Lillioja S, Esposito-Del Puente A, Nyomba BL, Raz I, Saad MF, Swinburn BA, Knowler WC, Bogardus C, Ravussin E (1990) Low ratio of fat to carbohydrate oxidation as predictor of weight gain: study of 24-h RQ. Am J Physiol 259:E650–657Google Scholar
- 11.Ravussin E, Swinburn BA (1993) Metabolic predictors of obesity: cross-sectional versus longitudinal data. Int J Obes Relat Metab Disord 17 Suppl 3:S28–31; discussion S41–22Google Scholar
- 13.Saltzman E, Roberts SB (1996) Effects of energy imbalance on energy expenditure and respiratory quotient in young and older men: a summary of data from two metabolic studies. Aging (Milan, Italy) 8:370–378Google Scholar
- 26.Belle SH, Berk PD, Chapman WH, Christian NJ, Courcoulas AP, Dakin GF, Flum DR, Horlick M, King WC, McCloskey CA, Mitchell JE, Patterson EJ, Pender JR, Steffen KJ, Thirlby RC, Wolfe BM, Yanovski SZ (2013) Baseline characteristics of participants in the Longitudinal Assessment of Bariatric Surgery-2 (LABS-2) study. Surg Obes Relat Dis 9:926–935CrossRefGoogle Scholar