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Purpose: To investigate the effects of a 3-week weight-management program entailing moderate energy restriction, nutritional education, psychological counseling and three different exercise training (a: low intensity, LI: 40 % V'O 2 max; b: high intensity, HI: 70 % V'O 2 max; c: high-intensity interval training, HIIT), on body composition, energy expenditure and fat oxidation rate in obese adolescents., Methods: Thirty obese adolescents (age: 15-17 years, BMI: 37.5 kg m -2 ) participated in this study. Before starting (week 0, W0) and at the end of the weight-management program (week 3, W3), body composition was assessed by an impedancemeter; basal metabolic rate (BMR), energy expenditure and substrate oxidation rate were measured during exercise and post-exercise recovery by indirect calorimetry., Results: At W3, body mass (BM) and fat mass (FM) decreased significantly in all groups, the decreases being significantly greater in the LI than in the HI and HIIT subgroups (BM: -8.4 ± 1.5 vs -6.3 ± 1.9 vs -4.9 ± 1.3 kg and FM: -4.2 ± 1.9 vs -2.8 ± 1.2 vs -2.3 ± 1.4 kg, p < 0.05, respectively). V'O 2 peak, expressed in relative values, changed significantly only in the HI and HIIT groups by 0.009 ± 0.005 and 0.007 ± 0.004 L kg FFM -1  min -1 (p < 0.05). Furthermore, the HI and HIIT subgroups exhibited a greater absolute rate of fat oxidation between 50 and 70 % V'O 2 peak at W3. No significant changes were observed at W3 in BMR, energy expenditure during exercise and post-exercise recovery., Conclusion: A 3-week weight-management program induced a greater decrease in BM and FM in the LI than in the HI and HIIT subgroups, and greater increase in V'O 2 peak and fat oxidation rate in the HI and HIIT than in the LI subgroup.

The objective was to investigate the effects of a 3- week weight-management program including moderate energy restriction and exercise training at 2 intensities [low intensity (LI): 40% and high intensity (HI): 70% maximal oxygen uptake (V'O(2)max)] on body composition, energy expenditure, and fat oxidation rate in severely obese adolescents. Twenty obese adolescents, aged 15-17 yr (body mass index: 37.5 kg/m(2); 38.2% fat mass) participated in this study. Before starting (week 0, W0) and at the end of the weight-management period (week 3,W3), body composition was assessed by a multifrequency tetrapolar impedancemeter; basal metabolic rate (BMR), energy expenditure, and substrate oxidation rate during exercise and post-exercise recovery by indirect calorimetry. At W3, body mass and fat mass decreased significantly (p<0.005) in all groups, and the decreases were significantly greater in the LI than in the HI group (-8.1±1.6 vs -5.9±1.6 kg and -4.2±1.9 vs -2.3±1.7 kg, p<0.05, respectively). Predicted V'O(2)max, expressed in relative values, changed significantly only in the HI group by +0.010±0.006 l/(kg fat-free mass × min) (p=0.010). By contrast, no significant changes were observed at W3 in BMR, energy expenditure, and substrate oxidation rate during exercise and post-exercise recovery. In conclusion, LI (40% of V'O(2)max) physical activity favors fat oxidation and it seems advisable to encourage obese adolescents to perform LI physical activity which is more feasible and acceptable than intense exercise.

The physical activity ratio (PAR) values are commonly used to convert subjects' physical activity recalls into estimates of daily energy expenditure (DEE). A PAR is defined as the ratio between energy expenditure corresponding to a sedentary or a physical activity (kJ/min) and basal metabolic rate [(BMR) kJ/min]. The objective of the present study was to determine the PAR for different sedentary and physical activities in obese adolescents. Thirty-three obese adolescents [mean body mass index: 35.1 kg/m2; 40.3 % fat mass] aged 11 to 17 yr participated in this study. BMR was assessed by indirect calorimetry after an overnight fast by means of an open-circuit, indirect computerised calorimetry with a rigid, transparent, ventilated canopy. Energy expenditures corresponding to various sedentary and physical activities in free-living conditions were determined using a portable metabolic unit, and body composition by bioelectrical impedance analysis (BIA). The PAR of each activity was obtained by dividing the assessed energy expenditure by BMR. In this study, the PAR of various sedentary and physical activities did not vary significantly with sex, age, and body mass. Thus, the data for boys and girls were combined and the PAR for 27 sedentary and physical activities were determined. The PAR values can be applied to determine the mean DEE (kJ) using the specific equation considering BMR (kJ/min), PAR, and duration (min) of each activity performed by the subject during the 24 h. This information will be useful to health-care professionals because estimation of DEE in obese adolescents is necessary in order to prescribe an adequate dietary therapy to induce a desired level of energy deficit.

Objective: To investigate the effects of an 8-month multidisciplinary weight-control program, including 2 h/week of moderate physical activity, nutritional education lessons and psychological follow-up, on body composition and lipid oxidation rate during exercise in obese children., Design: Nineteen (7 boys and 12 girls) obese children, aged 8-12 yr [mean body mass index (BMI) z-score: 2.3 and fat mass: 35.8%] participated in this study. Before and at the end of the weight-control period body composition was assessed by bioelectrical impedance, lipid oxidation rate by indirect calorimetry during a graded exercise test, and time devoted to various activities and energy intake in free-living conditions by questionnaire., Results: All children completed the study, at the end of which BMI decreased significantly by mean 0.6+/-0.5 and 0.5+/-0.8 kg/m2, in boys and girls, respectively (p<0.05), and fat mass (FM) decreased by 1.7+/-2.8 and 1.4+/-1.3 kg in boys and girls, respectively (p<0.05). In addition, lipid oxidation rate during exercise increased significantly throughout the graded exercise test up to 21% at maximal lipid oxidation rate which happened at 48+/-5% of maximal oxygen uptake (VO2max), corresponding to 64+/-5% of maximal heart rate. Time spent at sedentary and very light physical activities decreased (p<0.001) to the benefit of recreational activities at home., Conclusions: Multidisciplinary weight-control program, with moderate-intensity physical activities, induced decreases in FM without decreases in free FM, increases in VO2max, lipid oxidation rate during exercise, and time devoted to recreational activities in free-living conditions.

The objectives of the present study were to develop and cross-validate new equations for predicting resting energy expenditure (PREE) in severely obese Italian males, and to compare their accuracy with those of the Harris-Benedict, WHO/ FAO/UNU, Huang, Owen, Mifflin, Livingston, Nelson, Bernstein, and Cunnimgham equations in order to predict resting energy expenditure (REE), using the Bland-Altman method. One hundred and sixty-four severely obese males [mean body mass index (BMI): 45.4 kg/m2; 50.2% fat mass), aged 20 to 65 yr participated in this study. REE was measured by indirect calorimetry and body composition by bioelectrical analysis. Equations were derived by stepwise multiple regression analysis using a calibration group and tested against the validation group. Two new specific equations, based on anthropometric [REE=Weight x 0.048 + Height x 4.655 - age x 0.020 - 3.605 (R2=0.68, SE=1.14 MJ/d)] or body composition parameters [REE=fat free mass (FFM) x 0.081 + fat mass (FM) x 0.049 - age x 0.019 - 2.194 (R2=0.65, SE=1.15 MJ/d)], were generated. Mean PREE were not different from the mean measured REE (MREE) (<1%, p<0.001), REE being predicted accurately (95-105% of MREE) in 66 and 62% of subjects, respectively. The Harris-Benedict, WHO/FAO/UNU, Huang and Owen equations showed mean differences lower than 5% and PREE was accurate in less than 30% of subjects. The Mifflin, Livingston, and Nelson equations showed a mean PREE underestimation >7% (p<0.001) and PREE was accurate in less than 25% of subjects. The Bernstein and Cunningham equations showed a greater PREE underestimation (>22%, p<0.001) in more than 85% of subjects. The new prediction equations allow an accurate estimation of REE in groups of severely obese males and result in lower mean differences and lower limits of agreement between PREE and MREE than the commonly used equations.

The objective of the present study was to compare resting energy expenditure (REE) calculated by different predictive equations (McDuffie, Derumeaux, Tverskaya, Schofield, FAO/WHO/ UNU, Harris-Benedict and Lazzer-Sartorio) to REE measured in severely obese Caucasian children and adolescents. Two hundred and eighty-seven obese children and adolescents (121 males, 166 females, mean age: 14.5 yr, mean body mass index (BMI) z-score: 3.3) participated in this study. REE was measured (MREE) by indirect calorimetry and body composition by bioelectrical impedance analysis. The FAO/WHO/UNU equations showed the lowest mean difference between predicted resting energy expenditure (PREE) and MREE (+0.2%, p=ns), but the higher SD (+/-1.16 MJ) and the PREE were accurate in 26% of subjects. The Tverskaya, Derumeaux and Harris-Benedict equations significantly underestimated REE in all children and adolescents (-7.6, -4.1, and -2.4%, respectively, p<0.05), while the Schofield and McDuffie equations overestimated REE (+2.5, +5 and 25%, respectively, p<0.05). By contrast, the Lazzer-Sartorio equations showed the greater agreement and accuracy (in 55% of subjects) between mean PREEs and MREE for all children and adolescents, as well as for boys and girls (+1.6%, p=ns). In conclusion, Lazzer-Sartorio equations showed an accurate estimation of REE in groups of severely obese children and adolescents, resulting in lower mean differences and SD and higher accuracy between PREE and MREE than the other equations considered in this study.

The aims of the present study were to develop and cross-validate new equations for predicting resting energy expenditure (PREE) in severely obese Italian women, and to compare their accuracy with those of the Harris-Benedict, Bernstein, WHO/FAO/UNU, Owen, Mifflin, Nelson, Siervo, Huang and Livingston equations to predict REE, using the Bland-Altman method. One hundred and eighty two women [mean body mass index (BMI) 45.6 kg/m2; 56.7% fat mass (FM)], aged 19 to 60 yr participated in this study. REE was measured by indirect calorimetry and body composition by bioelectrical analysis. Equations were derived by stepwise multiple regression analysis, using a calibration group and tested against the validation group. Two new specific equations based on anthropometric REE=Weightx0.042+Heightx3.619-2.678 (R2=0.66, SE=0.56 MJ) or body composition parameters REE=FFMx0.067+FMx0.046+1.568 (R2=0.63, SE=0.58 MJ) were generated. Mean PREE were no different from the mean measured resting energy expenditure (MREE) (<1%, p>0.800) and REE was predicted accurately (95-105% of MREE) in 60% of subjects. The WHO/FAO/UNU, Harris-Benedict and Siervo equations showed mean differences <2% and PREE was accurate in <44% of subjects. The Huang, Mifflin and Livingston equations showed a mean PREE underestimation (>5.0%, p<0.001) and PREE was accurate in <38% of subjects. The Owen, Bernstein and Nelson equations showed a greater PREE underestimation (>14%, p<0.001) in >90% of subjects. The new prediction equations allow an accurate estimation of REE in groups of severely obese women and result in lower mean differences and lower limits of agreement between PREE and MREE than commonly used equations.