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ABSTRACT: BACKGROUND: Roux-en-Y gastric bypass (RYGB) surgery is an effective tool for long-term weight loss. Mechanisms underlying the effectiveness of such surgery might result not only from the anatomic changes due to the procedure, but also from favorable changes in energy metabolism. Our objective was to evaluate the respiratory quotient (RQ), resting metabolic rate (RMR), and diet-induced thermogenesis (DIT) among clinically severe obese patients (control group) and patients who had undergone RYGB ≥1 year previously. The setting was Gastrocirurgia de Brasilia (Brasilia, Brazil). METHODS: The present study was cross-sectional and involved 35 clinically severe obese patients (body mass index ≥40 kg/m(2) or body mass index ≥35 kg/m(2) with co-morbidities) as the control group and 34 RYGB patients who had undergone the procedure ≥12 months previously (RYGB group). The anthropometric data (height and weight) were determined for both groups, and the RMR and RQ were measured using indirect calorimetry after a 12-hour fast. Patients then received a standard meal, and DIT was determined. The RMR and DIT were also adjusted per kilogram of body weight (BW), i.e BW-adjusted RMR and BW-adjusted DI. RESULTS: The BW-adjusted RMR and RQ did not differ between the 2 groups in the fasting period. However, the DIT of the RYGB group, whether absolute or BW-adjusted, was >200% that of the control group (P <.0001). The BW-adjusted DIT of the RYGB group correlated significantly with the percentage of excess weight loss (P = .0097). The postprandial RQ value among the RYGB group was also significantly (P <.0001) greater than that of the control group, suggesting an increased use of carbohydrates. CONCLUSION: Postprandial changes in energy expenditure and fuel use might contribute, in part, to the effectiveness of weight loss as a result of the RYGB procedure.
Surgery for Obesity and Related Diseases 07/2012; · 3.93 Impact Factor
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ABSTRACT: Weight loss may decrease the energy expenditure (EE) because of changes in body composition (BC). The reduction in EE may contribute, in part, to weight regain. Experimental studies in animals indicate that Roux-en-Y Gastric Bypass (RYGB) increases the resting metabolic rate (RMR) when adjusted for body weight (BW). Thus, the aim of this study was to assess the clinical effects of RYGB on EE in patients who have undergone RYGB.
The study was prospective and included 46 RYGB patients whose RMR was assessed prior to and at least 6 months post-surgery by indirect calorimetry. BW and BC were measured at these same time points using bioelectric impedance. RMR was adjusted for changes in BW, i.e., kilocalories per kilogram. Statistical tests were used to analyze the results.
The BW-adjusted RMR (kilocalories per kilogram) increased post-RYGB by 17.66 % (p < 0.0001). RMR adjusted for BW was negatively correlated to the total percentage of body fat preoperatively (r = -0.30729, p = 0.0378) and postoperatively (r = -0.46731, p = 0.0011) and was positively correlated to the fat-free mass percentage (%FFM) both preoperatively and postoperatively. Furthermore, BW-adjusted RMR and %FFM were positively correlated to percent excess weight loss (r = 0.55398, p < 0.0001 and r = 0.31677, p = 0.0283, respectively).
Weight loss following RYGB is associated with an increase in BW-adjusted RMR and with %FFM. An increase in energy expenditure post-RYGB may be responsible, in part, for successful long-term weight loss of the RYGB procedure.
Obesity Surgery 05/2012; 22(9):1450-5. · 3.29 Impact Factor
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ABSTRACT: Since low basal metabolic rate (BMR) is a risk factor for weight regain, it is important to measure BMR before bariatric surgery. We aimed to evaluate the BMR among clinically severe obese patients preoperatively. We compared it with that of the control group, with predictive formulas and correlated it with body composition.
We used indirect calorimetry (IC) to collect BMR data and multifrequency bioelectrical impedance to collect body composition data. Our sample population consisted of 193 patients of whom 130 were clinically severe obese and 63 were normal/overweight individuals. BMR results were compared with the following predictive formulas: Harris-Benedict (HBE), Bobbioni-Harsch (BH), Cunningham (CUN), Mifflin-St. Jeor (MSJE), and Horie-Waitzberg & Gonzalez (HW & G). This study was approved by the Ethics Committee for Research of the University of Brasilia. Statistical analysis was used to compare and correlate variables.
Clinically severe obese patients had higher absolute BMR values and lower adjusted BMR values (p < 0.0001). A positive correlation between fat-free mass and a negative correlation between body fat percentage and BMR were found in both groups. Among the clinically severe obese patients, the formulas of HW & G and HBE overestimated BMR values (p = 0.0002 and p = 0.0193, respectively), while the BH and CUN underestimated this value; only the MSJE formulas showed similar results to those of IC.
The clinically severe obese patients showed low BMR levels when adjusted per kilogram per body weight. Body composition may influence BMR. The use of the MSJE formula may be helpful in those cases where it is impossible to use IC.
Obesity Surgery 04/2012; 22(8):1257-62. · 3.29 Impact Factor
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ABSTRACT: Bariatric surgery, a highly successful treatment for obesity, requires adherence to special dietary recommendations to insure the achievement of weight loss goals and weight maintenance. Postoperative consumption of protein is linked to satiety induction, nutritional status, and weight loss. Hence, we conducted an extensive literature review to identify studies focused on the following: protein and nutritional status; recommendations for dietary protein intake; the effects of protein-rich diets; and associations between dietary protein intake and satiety, weight loss, and body composition. We found that there have been few studies on protein intake recommendations for bariatric patients. Dietary protein ingestion among this population tends to be inadequate, potentially leading to a loss of lean body mass, reduced metabolic rates, and physiological damage. Conversely, a protein-rich diet can lead to increased satiety, enhanced weight loss, and improved body composition. The quality and composition of protein sources are also very important, particularly with respect to the quantity of leucine, which helps to maintain muscle mass, and thus is particularly important for this patient group. Randomized studies among bariatric surgery patient populations are necessary to establish the exact quantity of protein that should be prescribed to maintain their nutritional status.
Obesity Surgery 05/2011; 21(11):1798-805. · 3.29 Impact Factor
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ABSTRACT: In bariatric surgery patients, weight loss and long-term weight maintenance are related to food intake and eating patterns. To improve the diet orientation in the bariatric surgery postoperative period, we assessed the postoperative eating patterns and related them to weight loss.
This was a transversal, analytical, and descriptive study that assessed body mass index (BMI) values and percentage of excess weight loss (%EWL) in patients who had undergone Roux-en-Y gastric bypass (RYGBP) surgery. The eating pattern and energy intake were investigated based on data collected through a 4-day food intake record. From these records, we assessed the number of daily meals, the quantity of food per meal, and calorie value of snacks between main meals. Based on these records, patients were classified under sweet-eating, snack-eating, or normal-eating patterns.
Seventy-five patients met our inclusion criteria. The normal-eating pattern group was the one with the greatest weight loss with an average %EWL of 71.4 +/- 21%, followed by the sweet-eating pattern with 69.9 +/- 16.8%, and the snack-eating pattern with 56.4 +/- 16.7%. This difference was significant only between the first and the third group (p = 0.04). The snack-eating patients had the highest caloric intake and highest number of daily meals (p < 0.01).
Postoperative eating pattern influenced postbariatric surgery weight loss. In the present study, the snack-eating pattern was associated with the worst weight loss outcome, followed by the sweet-eating and normal-eating patterns. A screening and a differential approach to patients according to their eating patterns may lead to better results of weight loss.
Obesity Surgery 10/2008; 19(9):1293-6. · 3.29 Impact Factor
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ABSTRACT: To correlate anthropometric data and respiratory muscle strength (RMS) of normal-weight and obese women.
The sample consisted of 103 sedentary women, divided into two groups: 57 obese and 46 normal-weight women. Waist circumference (WC) and hip circumference (HC) were measured to calculate the waist-to-hip ratio (WHR), and maximal respiratory pressures (Pmax) were determined using an analog vacuum manometer to ± 300 cm H2O. Body composition was measured using tetrapolar bioelectrical impedance analysis. Descriptive statistics was used for data analysis, in addition to the Student t test for independent samples, Pearson correlation, and stepwise multiple linear regression analysis. Significance level was set at p ≤ 0.05.
The analysis showed significant differences in Pmax of normal-weight women (PImax = -73.04±16.55 cm H2O and PEmax = 79.67±18.89 cm H2O) and obese women (PImax = -85.00±21.69 cm H2O and PEmax = 103.86±20.35 cm H2O). Anthropometric and manometric variables showed no significant correlation in both groups. When analyzing the influence of bioelectrical impedance on RMS, a positive correlation was observed between lean body mass and PImax.
Bioelectrical impedance and obesity showed a direct correlation with RMS. WC and WHR had no influence on RMS of obese women; however, a relevance to risk factors for associated diseases was observed. We believe that these results are due to an adjustment to excess body weight over the years.
Revista da Associação Médica Brasileira 56(4):403-8. · 0.77 Impact Factor
