Diet-induced thermogenesis in postoperatve Roux-en-Y gastric bypass patients with weight regain.

BACKGROUND: Bariatric surgery has been shown to be an effective treatment for obesity. Changes in energy expenditure, especially through diet-induced thermogenesis (DIT), have been identified as one of the mechanisms to explain this success. However, not all patients are able to maintain healthy postoperative weight loss. Therefore, a question arises: In the weight regain after bariatric surgery, are these changes in energy metabolism still active? OBJECTIVE: To investigate if weight regain after Roux-en-Y gastric bypass (RYGB) surgery is associated with a lower diet-induced thermogenesis in the late postoperative period. SETTING: A cross-sectional study with the participants chosen from among the patients from a private practice. METHODS: This was a cross-sectional study where 3 groups of female patients were evaluated: (1) 20 patients with a RYGB postoperative time period of at least 2 years, who kept a healthy weight after surgery (loss of at least 50% of excess weight; Healthy group); (2) 19 patients with clinically severe obesity (BMI>40 kg/m(2), without co-morbidities and>35 kg/m(2), with co-morbidities; Pre group); (3) 18 patients who experienced weight regain after RYGB (Regain group). The 3 groups were submitted to indirect calorimetry to measure resting metabolic rate (RMR), respiratory quotient (RQ), and DIT. Immediately after the RMR measurement, a mixed meal of regular consistency was offered. Ten minutes after the food intake began, energy expenditure measurements were initiated continuing throughout the following 3 postprandial hours. Body composition was evaluated using multifrequency bioelectrical impedance. In subgroups of the studied population, glucose and insulin levels were measured at baseline and at 30, 60, 90, 120, and 180 minutes after feeding. The mean area under the curve (AUC) between the 3 groups and measurements at baseline were compared using the analysis of variance (ANOVA). RESULTS: The Healthy group had the highest weight adjusted RMR value compared with both the Pre and Regain group (23.03±3.02 kcal/kg; 16.18±2.94 kcal/kg; 17.11±3.28 kcal/kg, respectively; P<.0001). The Regain and Pre groups showed no difference for this variable. The weight-adjusted DIT (AUC 0-180 min) was about 42% and 34% higher in the Healthy group compared with the Pre and Regain groups, respectively (P<.0001). Lean body mass (kg) showed a positive correlation with the AUC of weight-adjusted DIT in the 3 groups. Multiple regression revealed that lean body mass was the only variable related to weight adjusted DIT, independent of group and other selected variables. CONCLUSION: Weight-adjusted DIT in the Regain group was smaller compared with the Healthy group, and with no difference compared with the Pre group. The lean body mass seems to have a positive association with diet-induced thermogenesis.

Comparison of weight loss, food consumption and frequency of vomiting among Roux-en-Y gastric bypass patients with or without constriction ring.

BACKGROUND: After Roux-en-Y gastric bypass to avoid rapid gastric emptying, dumping syndrome and regained weight due to possible dilation of the gastric pouch, was proposed to place a ring around the gastric pouch. AIM: To compare weight loss, consumption of macronutrients and the frequency of vomiting among patients who underwent Roux-en-Y gastric bypass with and without the placement of a constriction ring around the pouch. METHOD: A retrospective study, in which an analysis of medical records was carried out, collecting data of two groups of patients: those who underwent the operation with the placement of a constriction ring (Ring Group) and those who underwent without the placement of a ring (No-Ring Group). The food intake data were analyzed using three 24-hour recalls collected randomly in postoperative nutritional accompaniment. Data on the percentage of excess weight loss and the occurrence of vomiting were collected using the weight corresponding to the most recent report at the time of data collection. RESULTS: Medical records of 60 patients were analyzed: 30 from the Ring Group (women: 80%) and 30 from the No-Ring Group (women: 87%). The average time since the Ring Group underwent the operation was 88 ± 17.50 months, and for the No-Ring Group 51 ± 15.3 months. The percentage of excess weight loss did not differ between the groups. The consumption of protein (g), protein/kg of weight, %protein and fiber (g) were higher in the No-Ring Group. The consumption of lipids (g) was statistically higher in the Ring Group. The percentage of patients who never reported any occurrence was statistically higher in the No-Ring Group (80%vs.46%). The percentage who frequently reported the occurrence was statistically higher in the Ring Group (25%vs.0%). CONCLUSION: The placement of a ring seems to have no advantages in weight loss, favoring a lower intake of protein and fiber and a higher incidence of vomiting, factors that have definite influence in the health of the bariatric patient.

Diet-induced thermogenesis and respiratory quotient after Roux-en-Y gastric bypass surgery: a prospective study.

BACKGROUND: Studies in humans and other animals have shown that Roux-en-Y gastric bypass (RYGB) leads to increased energy expenditure (EE). We analyzed several components of EE, such as the respiratory quotient (RQ), resting metabolic rate (RMR), and diet-induced thermogenesis (DIT) among patients before and after RYGB. METHODS: In this prospective clinical study, RMR, DIT, and RQ were measured by indirect calorimetry (IC) in the same patients before and 12 months after RYGB (the preoperative and postoperative time points, respectively). Postprandial RQ and DIT were measured after patients consumed a standard ~270 kcal meal (62% carbohydrates, 12% proteins, and 26% lipids). RESULTS: The population studied consisted of 13 patients (mean age 40.8 ± 6.7 years, 85% female).At the postoperative (postop) time point, patients showed higher weight-adjusted RMR compared with the preoperative (preop) time point (P<.01). The absolute and weight-adjusted metabolic rates 20 minutes after the meal were increased postoperatively (P<.0001) but not preoperatively (P = 0.2962) (DIT); this increase in RQ was significantly higher in the postop than in the preop time point. CONCLUSION: The observed patients showed increased EE, DIT, and RQ after RYGB surgery. These data may serve as important physiologic factors contributing to the loss and maintenance of weight after RYGB.

Comparison of weight loss, food consumption and frequency of vomiting among Roux-en-Y gastric bypass patients with or without constriction ring / Comparação da perda de peso, consumo alimentar e frequência de vômitos entre pacientes do bypass gástrico em Y-de-Roux com e sem colocação de anel de contenção

BACKGROUND: After Roux-en-Y gastric bypass to avoid rapid gastric emptying, dumping syndrome and regained weight due to possible dilation of the gastric pouch, was proposed to place a ring around the gastric pouch. AIM: To compare weight loss, consumption of macronutrients and the frequency of vomiting among patients who underwent Roux-en-Y gastric bypass with and without the placement of a constriction ring around the pouch. METHOD: A retrospective study, in which an analysis of medical records was carried out, collecting data of two groups of patients: those who underwent the operation with the placement of a constriction ring (Ring Group) and those who underwent without the placement of a ring (No-Ring Group). The food intake data were analyzed using three 24-hour recalls collected randomly in postoperative nutritional accompaniment. Data on the percentage of excess weight loss and the occurrence of vomiting were collected using the weight corresponding to the most recent report at the time of data collection. RESULTS: Medical records of 60 patients were analyzed: 30 from the Ring Group (women: 80%) and 30 from the No-Ring Group (women: 87%). The average time since the Ring Group underwent the operation was 88±17.50 months, and for the No-Ring Group 51±15.3 months. The percentage of excess weight loss did not differ between the groups. The consumption of protein (g), protein/kg of weight, %protein and fiber (g) were higher in the No-Ring Group. The consumption of lipids (g) was statistically higher in the Ring Group. The percentage of patients who never reported any occurrence was statistically higher in the No-Ring Group (80%vs.46%). The percentage who frequently reported the occurrence was statistically higher in the Ring Group (25%vs.0%). CONCLUSION: The placement of a ring seems to have no advantages in weight loss, favoring a lower intake of protein and fiber and a higher incidence of vomiting, factors ...

RACIONAL: Após bypass gástrico em Y-de-Roux e a fim de evitar o rápido esvaziamento gástrico, amenizar a síndrome de dumping e evitar o reganho de peso devido à possível dilatação da anastomose gastrojejunal, foi idealizada a colocação de um anel ao redor do reservatório gástrico. OBJETIVO: Comparar a perda de peso, o consumo de macronutrientes e a frequência de vômitos entre pacientes que realizaram o bypass gástrico em Y-de-Roux com e sem a colocação do anel de contenção. MÉTODOS: Estudo retrospectivo na análise de prontuários para a coleta dos dados de dois grupos de pacientes: os que realizaram o bypass gástrico em Y-de-Roux com a colocação do anel de contenção ao redor da bolsa gástrica (grupo com anel) e sem a colocação do anel (grupo sem anel). Os dados de consumo alimentar foram analisados através de três recordatórios de 24 horas coletados aleatoriamente nos atendimentos nutricionais do pós-operatório. Os dados quanto à porcentagem de perda do excesso de peso e ocorrência de vômitos foram coletados utilizando o peso e o relato mais recente em relação ao período da coleta. RESULTADOS: Analisaram-se prontuários de 60 pacientes: 30 do grupo com anel e 30 do grupo sem anel. A média do tempo de operado do grupo com anel foi de 88±17,5 meses, e do grupo sem anel 51±15,3 meses. A porcentagem de perda do excesso de peso não diferiu entre os grupos. O consumo de proteína (g), proteína/kg de peso, %proteína e fibras (g) foi estatisticamente superior no grupo sem anel. O consumo de lipídios (g) foi estatisticamente superior no grupo com anel. A porcentagem de pacientes que nunca relataram a ocorrência foi estatisticamente superior no grupo sem anel (80%vs46%). A porcentagem ...

Validation of ultrasound examination for assessment of the abdominal visceral fat in clinically serious obese patient.

BACKGROUND: Computerized tomography is the gold-standard for measurement of abdominal visceral fat. However, it is costly and involves submitting patients to ionizing radiation. AIM: To validate the use of ultrasonography in assessing abdominal visceral fat among clinically serious obese patients of both genders. METHODS: The sample included adult patients with clinically serious obesity with body mass index of 40 kg/m2 or from 35 kg/m(2) to 40 kg/m2 with co-morbidities. Abdominal visceral fat thickness was measured using ultrasound and tomography. Two ultrasonographic exams were conducted to assess the interobserver reproducibility among a patient subsample. Validation was done by comparing these results with the tomographic findings. RESULTS: The study included 13 patients (61.54% female) with an average BMI of 38.82 kg/m2. In terms of validation, the result obtained from applying the Pearson correlation coefficient was equal to 0.94 (p = 0.0005), showing a strong positive correlation between the two measurements. As for the results for reproducibility, the interobserver was equal to 0.822, with a confidence interval of 95% (-0.076 to 0.980), revealing good interobserver agreement. The average difference between the two ultrasound interobserver examination was equal to 0.10 ± 1.51 (p=0.8898) and so not significant. Interobserver bias was also not significant. CONCLUSION: The validation of ultrasonographic examination to replace tomographic method in assessing abdominal visceral fat among clinically serious obese patients was effective. The ultrasound measurement is independent of the examiner.

Validação da ultrassonografia para a avaliação da gordura abdominal visceral em obesos clinicamente graves / Validation of ultrasound examination for assessment of the abdominal visceral fat in clinically serious obese patient

RACIONAL: A tomografia computadorizada é o padrão-ouro para a medida da gordura abdominal visceral. No entanto é dispendiosa e envolve submeter os doentes à radiação ionizante. OBJETIVO: Validar o método ultrassonográfico para avaliação da gordura abdominal visceral em obesos clinicamente graves de ambos os sexos. MÉTODOS: A amostra incluiu adultos com obesidade clinicamente grave que apresentavam índice de massa corporal de 40kg/m² ou entre 35kg/m² e 40kg/m² com comorbidades associadas. Os exames realizados para medição da espessura da gordura visceral foram: ultrassonografia e de tomografia computadorizada. Foram realizados dois exames para avaliação da reprodutibilidade interobservador em uma subamostra de pacientes. O estudo ultrassonográfico foi validado comparando-o aos resultados do exame tomográfico. RESULTADOS: Participaram do estudo 13 pacientes, sendo 61,54% mulheres com IMC médio de 38,82kg/m². A validação foi feita pelo coeficiente de correlação de Pearson resultando ser igual a 0,94 (p = 0,0005). Evidenciou-se correlação positiva e forte entre as duas medidas. Quanto aos resultados da reprodutibilidade, o coeficiente de correlação intraclasse interobservador foi igual a 0,822 com intervalo de confiança de 95% (-0,076 a 0,980), o que revela boa concordância interobservador. A diferença média entre os dois observadores na ultrassonografia foi igual a 0,10 ± 1,51 (p = 0,8898), não significativa e sem viés significativo interobservador. CONCLUSÃO: Foi efetiva a validação do exame ultrassonográfico como substituição ao tomográfico para avaliar a gordura abdominal visceral entre obesos clinicamente graves. A medida ultrassonográfica independe do examinador.

BACKGROUND: Computerized tomography is the gold-standard for measurement of abdominal visceral fat. However, it is costly and involves submitting patients to ionizing radiation. AIM: To validate the use of ultrasonography in assessing abdominal visceral fat among clinically serious obese patients of both genders. METHODS: The sample included adult patients with clinically serious obesity with body mass index of 40kg/m2 or from 35kg/m2 to 40kg/m2 with co-morbidities. Abdominal visceral fat thickness was measured using ultrasound and tomography. Two ultrasonographic exams were conducted to assess the interobserver reproducibility among a patient subsample. Validation was done by comparing these results with the tomographic findings. RESULTS: The study included 13 patients (61.54% female) with an average BMI of 38.82 kg/m2. In terms of validation, the result obtained from applying the Pearson correlation coefficient was equal to 0.94 (p = 0.0005), showing a strong positive correlation between the two measurements. As for the results for reproducibility, the interobserver was equal to 0.822, with a confidence interval of 95% (-0.076 to 0.980), revealing good interobserver agreement. The average difference between the two ultrasound interobserver examination was equal to 0.10 ± 1.51 (p=0.8898) and so not significant. Interobserver bias was also not significant. CONCLUSION: The validation of ultrasonographic examination to replace tomographic method in assessing abdominal visceral fat among clinically serious obese patients was effective. The ultrasound measurement is independent of the examiner.

Diet-induced thermogenesis and respiratory quotient after Roux-en-Y gastric bypass.

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.