Muscle Strength of Lower Limbs as a Postoperative Predictor in Bariatric Surgery.

OBJECTIVE: The aim of our study was to assess postoperative lower limbs muscle strength (MS) as a predictor of late surgical success (36 months). METHODS: Body composition analyses and isokinetic dynamometry evaluation were performed before (T0: n=123), six months (T1: n=123) and 36 months (T2: n=79) after Roux-en-y gastric bypass (RYGB). Surgical success (SS) was defined as ≥ 50% excess weight loss (EWL) 36 months after surgery or ≤ 50% surgical failure (SF). RESULTS: There was no difference between relative MS extension (Ext) and flexion (Flex) in T1 and T2. There was also, no difference between relative MS Ext and Flex in T1 and T2 between patients with SS and SF. There was a difference in relative MS Ext (144.9 ± 39.8 Nm/kg x 125.5 ± 29.2 Nm/kg; p=0.04) and Flex (73.6 ± 21.8 Nm/kg x 60.4 ± 15.8 Nm/kg; p=0.02) between SS and SF patients only in T2. Patients with an increment in Ext and Flex MS ≥4 Nm/kg at T1 had approximately 76% of SS at 36 months. CONCLUSION: An increase of lower limbs MS ≥4 Nm/kg 6 months after RYGB predicts SS at 36 months. CLINICALTRIALS: gov ID: NCT04129801.

Postoperative Resting Metabolic Rate and Successful Weight Loss After Roux-en-Y Gastric Bypass.

OBJECTIVE: To analyze whether changes in RMR 6 months after RYGB could be a predictor of weight loss on late follow-up. METHODS: Prospective study of 45 individuals submitted to RYGB in a university tertiary care hospital. Body composition was evaluated by bioelectrical impedance analysis and RMR by indirect calorimetry before (T0), 6 (T1), and 36 months (T2) after surgery. RESULTS: RMR/day was lower in T1 (1.552 ± 275 kcal/day) than in T0 (1734 ± 372 kcal/day; p < 0.001) with a return to similar values at T2 (1.795 ± 396 kcal/day; p < 0.001). In T0, there was no correlation between RMR/kg and body composition. In T1, there was a negative correlation between RMR and BW, BMI, and % FM, and a positive correlation with % FFM. The results in T2 were similar to T1. There was a significant increase in RMR/kg between T0, T1, and T2 (13.6 ± 2.2 kcal/kg, 16.9 ± 2.7 kcal/kg, and 19.9 ± 3.4 kcal/kg) in the total group and according to gender. Eighty percent of the patients who had increased RMR/kg ≥ 2 kcal at T1 achieved > 50% EWL in T2, particularly in women (odds ratio: 27.09, p < 0.037). CONCLUSIONS: The increase in RMR/kg after RYGB is a major factor related to a satisfactory % excess weight loss on late follow-up.

Very low-calorie diet in candidates for bariatric surgery: change in body composition during rapid weight loss.

OBJECTIVE: To analyze the changes in the body composition of morbidly obese patients induced by a very low-calorie diet. METHODS: We evaluated 120 patients selected from a university hospital. Body composition was assessed before and after the diet provided during hospitalization, and changes in weight, body mass index, and neck, waist and hip circumferences were analyzed. Bioimpedance was used to obtain body fat and fat-free mass values. The data were categorized by gender, age, body mass index and diabetes diagnosis. RESULTS: The patients consumed the diet for 8 days. They presented a 5% weight loss (without significant difference among groups), which represented an 85% reduction in body fat. All changes in body circumference were statistically significant. There was greater weight loss and a greater reduction of body fat in men, but the elderly showed a significantly higher percentage of weight loss and greater reductions in body fat and fat-free mass. Greater reductions in body fat and fat-free mass were also observed in superobese patients. The changes in the diabetic participants did not differ significantly from those of the non-diabetic participants. CONCLUSIONS: The use of a VLCD before bariatric surgery led to a loss of weight at the expense of body fat over a short period, with no significant differences in the alteration of body composition according to gender, age, body mass index and diabetes status.

Very low-calorie diet in candidates for bariatric surgery: change in body composition during rapid weight loss

OBJECTIVE: To analyze the changes in the body composition of morbidly obese patients induced by a very low-calorie diet. METHODS: We evaluated 120 patients selected from a university hospital. Body composition was assessed before and after the diet provided during hospitalization, and changes in weight, body mass index, and neck, waist and hip circumferences were analyzed. Bioimpedance was used to obtain body fat and fat-free mass values. The data were categorized by gender, age, body mass index and diabetes diagnosis. RESULTS: The patients consumed the diet for 8 days. They presented a 5% weight loss (without significant difference among groups), which represented an 85% reduction in body fat. All changes in body circumference were statistically significant. There was greater weight loss and a greater reduction of body fat in men, but the elderly showed a significantly higher percentage of weight loss and greater reductions in body fat and fat-free mass. Greater reductions in body fat and fat-free mass were also observed in superobese patients. The changes in the diabetic participants did not differ significantly from those of the non-diabetic participants. CONCLUSIONS: The use of a VLCD before bariatric surgery led to a loss of weight at the expense of body fat over a short period, with no significant differences in the alteration of body composition according to gender, age, body mass index and diabetes status.

TRUNK BODY MASS INDEX: A NEW REFERENCE FOR THE ASSESSMENT OF BODY MASS DISTRIBUTION.

BACKGROUND: Body mass index (BMI) has some limitations for nutritional diagnosis since it does not represent an accurate measure of body fat and it is unable to identify predominant fat distribution. AIM: To develop a BMI based on the ratio of trunk mass and height. METHODS: Fifty-seven patients in preoperative evaluation to bariatric surgery were evaluated. The preoperative anthropometric evaluation assessed weight, height and BMI. The body composition was evaluated by bioimpedance, obtaining the trunk fat free mass and fat mass, and trunk height. Trunk BMI (tBMI) was calculated by the sum of the measurements of the trunk fat free mass (tFFM) and trunk fat mass (tFM) in kg, divided by the trunk height squared (m2)). The calculation of the trunk fat BMI (tfBMI) was calculated by tFM, in kg, divided by the trunk height squared (m2)). For the correction and adjustment of the tBMI and tfBMI, it was calculated the relation between trunk extension and height, multiplying by the obtained indexes. RESULTS: The mean data was: weight 125.3±19.5 kg, height 1.63±0.1 m, BMI was 47±5 kg/m2) and trunk height was 0.52±0,1 m, tFFM was 29.05±4,8 kg, tFM was 27.2±3.7 kg, trunk mass index was 66.6±10.3 kg/m², and trunk fat was 32.3±5.8 kg/m². In 93% of the patients there was an increase in obesity class using the tBMI. In patients with grade III obesity the tBMI reclassified to super obesity in 72% of patients and to super-super obesity in 24% of the patients. CONCLUSION: The trunk BMI is simple and allows a new reference for the evaluation of the body mass distribution, and therefore a new reclassification of the obesity class, evidencing the severity of obesity in a more objectively way.

Resting metabolic rate and weight loss after bariatric surgery.

BACKGROUND: There is an increased interest in understanding how variation in body composition (BC) and energy expenditure is related to successful weight loss after surgery. It has been suggested that low resting metabolic rate (RMR) could be associated with poor weight loss. OBJECTIVES: To determine the relation among changes in BC, RMR, and weight loss after bariatric surgery. SETTING: University tertiary care hospital, Brazil. METHODS: A cohort of 45 patients submitted to bariatric surgery was prospectively studied. BC was evaluated by bioelectrical impedance analysis and RMR by indirect calorimetry before and 6 months after surgery. The RMR value was adjusted per kilogram of weight (RMR/kg). The patients were divided in 4 groups, based on patterns of change in the RMR/kg after surgery. The RMR/kg could decrease (group 1), remain stable (group 2), have a small increase (group 3), or have a major increase (group 4). RESULTS: A significant relation between fat-free mass and RMR for both pre- (P<.01) and postoperative periods (P<.01) was observed. Excess weight loss had a significantly correlation only with post-RMR/kg (P<.01). The pattern of change in RMR/kg was strongly correlated with weight loss, considering an excess weight loss>50% a successful weight loss: No patients achieved success in group 1; 61% of patients did in group 2; 80% di in group 3; and all patients in group 4 had successful weight loss. CONCLUSIONS: We demonstrate a clearly correlation between the postoperative RMR and weight loss. The increase in RMR/kg after surgery is a major factor related to a satisfactory excess weight loss after surgery.

Trunk body mass index: a new reference for the assessment of body mass distribution / índice de massa corpórea do tronco: nova referência para avaliação da distribuição da massa corporal

ABSTRACT Background: Body mass index (BMI) has some limitations for nutritional diagnosis since it does not represent an accurate measure of body fat and it is unable to identify predominant fat distribution. Aim: To develop a BMI based on the ratio of trunk mass and height. Methods: Fifty-seven patients in preoperative evaluation to bariatric surgery were evaluated. The preoperative anthropometric evaluation assessed weight, height and BMI. The body composition was evaluated by bioimpedance, obtaining the trunk fat free mass and fat mass, and trunk height. Trunk BMI (tBMI) was calculated by the sum of the measurements of the trunk fat free mass (tFFM) and trunk fat mass (tFM) in kg, divided by the trunk height squared (m2)). The calculation of the trunk fat BMI (tfBMI) was calculated by tFM, in kg, divided by the trunk height squared (m2)). For the correction and adjustment of the tBMI and tfBMI, it was calculated the relation between trunk extension and height, multiplying by the obtained indexes. Results: The mean data was: weight 125.3±19.5 kg, height 1.63±0.1 m, BMI was 47±5 kg/m2) and trunk height was 0.52±0,1 m, tFFM was 29.05±4,8 kg, tFM was 27.2±3.7 kg, trunk mass index was 66.6±10.3 kg/m², and trunk fat was 32.3±5.8 kg/m². In 93% of the patients there was an increase in obesity class using the tBMI. In patients with grade III obesity the tBMI reclassified to super obesity in 72% of patients and to super-super obesity in 24% of the patients. Conclusion: The trunk BMI is simple and allows a new reference for the evaluation of the body mass distribution, and therefore a new reclassification of the obesity class, evidencing the severity of obesity in a more objectively way.

RESUMO Racional: O índice de massa corporal (IMC) para diagnóstico nutricional apresenta limitações, pois não representa medida precisa da adiposidade corporal, podendo assim subestimar a presença de obesidade. Objetivo: Desenvolver um índice de massa corporal baseado entre a relação da massa e altura do tronco. Método: Cinquenta e sete pacientes em preparo pré-operatório para cirurgia bariátrica foram submetidos à avaliação antropométrica (peso, altura e índice de massa corporal). Para cálculo do IMC do tronco foi avaliada a composição corporal pela bioimpedância, obtendo-se a massa livre de gordura e massa de gordura do tronco; a medida do tronco foi calculada pela diferença entre a altura a partir da sétima vértebra cervical e a extensão dos membros inferiores. O cálculo do IMC do tronco (IMCt) foi a soma das medidas da massa livre de gordura do tronco (MLGt) e massa de gordura do tronco (MGt), em kg, dividindo-se pelo quadrado da altura do tronco (m2)). O IMC de gordura do tronco (IMCgt) foi calculado utilizando a MGt, em kg, dividindo-a pelo quadrado da altura do tronco (m2)). Para correção e ajuste do IMCt e IMCgt foi calculada a relação entre os valores de extensão do tronco e da altura, multiplicando-se pelo valor dos índices obtidos. Resultados: As médias do peso e altura foram de 125,3±19,5 kg e 1,63 m±0,1, respectivamente, e do IMC de 47±5 kg/m2). A média da altura do tronco foi de 0,52±0,1 m, da MLGt de 29,05±4,8 kg, da MGt de 27,2±3,7 kg, do IMCt de 66,6±10,3 kg/m², e do IMCgt 32,3±5,8 kg/m². Em 93% dos pacientes houve aumento da classificação da gravidade da obesidade com o cálculo do IMCt . Nos pacientes com obesidade grau III, o IMCt alterou a classificação para super-obesidade em 72% dos pacientes e para super-super obesidade em 24% dos pacientes. Conclusão: O IMC do tronco é método antropométrico acessível e prático, que permite a reclassificação do IMC baseado na distribuição da massa do tronco, evidenciando de forma mais clara a gravidade da obesidade.

Muscle strength and body composition in severe obesity

OBJECTIVE: The aim of our study was to evaluate associations between maximum voluntary contraction torques of the lower limbs and body composition for subjects with severe obesity. METHODS: Body composition was evaluated by bioelectrical impedance analysis, and maximum voluntary contraction torques of the lower limbs were measured using an isokinetic dynamometer. One hundred thirty-two patients were enrolled (100 females and 32 males). Eighty-seven patients had a body mass index between 40 and 49.9 kg/m2 (the A group), and 45 patients had a body mass index between 50 and 59.9 kg/m2 (the B group). RESULTS: Absolute extension and flexion torques had weak associations with fat-free mass but a moderate association with absolute extension torque and fat-free mass of the lower limbs. There were no significant differences between the A and B groups with respect to absolute extension and flexion torques. For the A group, absolute extension and flexion torques were moderately associated with fat-free mass and with fat-free mass of the lower limbs. For the B group, there were only moderate associations between absolute extension and flexion torques with fat-free mass of the lower limbs. CONCLUSIONS: Our findings demonstrate that both groups exhibited similar absolute torque values. There were weak to moderate associations between absolute extension and flexion torques and fat-free mass but a moderate association with fat-free mass of the lower limbs. Individuals with severe obesity should strive for greater absolute torques, fat-free mass and especially fat-free mass of the lower limbs to prevent functional limitations and physical incapacity.