RESUMO
BACKGROUND: 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. METHODS: 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. 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). CONCLUSIONS: 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.
Assuntos
Metabolismo Energético , Derivação Gástrica , Obesidade Mórbida/metabolismo , Obesidade Mórbida/cirurgia , Adulto , Idoso , Composição Corporal , Índice de Massa Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida/fisiopatologia , Período Pós-Operatório , Período Pré-Operatório , Estudos Prospectivos , Resultado do Tratamento , Aumento de Peso , Redução de PesoRESUMO
BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
Assuntos
Cirurgia Bariátrica/métodos , Metabolismo Basal , Composição Corporal , Metaboloma , Obesidade Mórbida/metabolismo , Adolescente , Adulto , Índice de Massa Corporal , Calorimetria Indireta , Estudos Transversais , Impedância Elétrica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade Mórbida/fisiopatologia , Obesidade Mórbida/cirurgia , Seleção de Pacientes , Adulto JovemRESUMO
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.