 Methods: This cross-sectional study evaluated three female groups: 1 Postop RYGBP patients operated at least 2 years previously, with healthy weight at least 50 loss of excess weight - HW group ; 2 Clinically severe obese patients BMI 40 kgm2, without co-morbidities or 35 kgm2 with co-morbidities - OB group; 3 Post-op RYGBP WR patients at least 10 above post-op minimum weight and less than 50 loss of preop excess weight - WR group. All patients, from a private practice in Brasilia, were given indirect calorimetry examinations GERATHERM RESPIRATORY measuring resting metabolic rate RMR, respiratory exchange rate RER and DIT and collected urine during 24 hours for analysis. Immediately after RMR measurement, a solid mixed meal was served 270 kcal: 62 carbohydrate, 12 protein and 26 lipid. Remove? After ten minutes, successive PP energy expenditure measurements were taken after some minutes, viz: 10-20, 20-30, 30-40, 60-70, 70-80, 80-90, 110-120, 120- 130, 130-140, 160-170 and 170-180, accompanying a 3-hour measurement period. DIT, calculated for each interval, followed this equation: DIT PP Metabolic rate MR time interval - RMR. Correct? Mean areas under the curve AUC of all groups and baseline time measurements were compared using the analysis of variance test ANOVA. Between-group longitudinal changes were tested using a mixed-effects model analysis of variance for repeated measures. Showing a p-value 0.05, a Bonferroni correction was used. AUC was calculated by trapezoidal rule, considering significant a value of p 0.05. 