Association of protein-energy partitioning with body weight and body composition changes in adolescents with severe obesity.

BACKGROUND/OBJECTIVES: Body composition and protein-energy partitioning changes are important factors of body weight regulation, but have not been studied in the context of clinical obesity treatment setting. Thus, the aim of the present study was to investigate the pattern of body weight loss, body composition, and energy partitioning changes during a 9-month multidisciplinary weight loss program and 4-month follow up and to test the associations among these changes in adolescents with severe obesity. SUBJECTS/METHODS: Twenty-five adolescents (14.1 ± 1.5 years old; 13 girls) with severe obesity joined a pediatric obesity center for a 9-month inpatient multidisciplinary weight loss program. All participants performed body composition assessment (i.e. fat mass-FM, and fat-free mass-FFM) and completed a 36-h session in indirect calorimetric chamber before the start (T0), at the end of the intervention (T1) and 4 months follow-up to the intervention (T2). The protein-energy partitioning (P ratio) was calculated as urinary nitrogen loss/total energy expenditure over 24 hours. INTERVENTIONS: 9-month individualized multidisciplinary weight loss program consisting of lifestyle education, psychological support, physical activity, and dietary intervention. RESULTS: Initial P ratio was positively associated with changes in body weight from T0 to T1 (p = 0.038). The changes in FFM/FM were negatively associated with body weight changes in boys (p = 0.006) from T0 to T1 and in girls (p < 0.001) from T1 to T2. Urinary nitrogen excretion (p < 0.001) and total energy expenditure (p < 0.001) significantly decreased during the weight loss program while the P ratio did not significantly change. CONCLUSION: The present results suggest that baseline and changes in energy partitioning may be associated with changes in body weight in adolescents with severe obesity. In addition, sexual dimorphism in these patterns of change suggest the need for specific dietary and physical activity strategies in boys and girls to optimize body weight loss and to prevent or slow weight regain.

Energy cost of walking and body composition changes during a 9-month multidisciplinary weight reduction program and 4-month follow-up in adolescents with obesity.

The purpose of the present study was to investigate changes in the energy cost of locomotion during walking (Cw) related to changes in body mass (BM, kg) and body composition in adolescents with obesity. Twenty-six (12 boys and 14 girls) obese adolescents (mean: body mass index, 33.6 ± 3.7 kg·m-2; 42.7 ± 4.5% fat mass (FM)) followed a 9-month multidisciplinary inpatient weight-reduction program consisting of lifestyle education, moderate energy restriction, and regular physical activity in a specialised institution. At baseline (M0), the end of the 9-month program (M9), and after the 4-month follow-up (M13), oxygen consumption and carbon dioxide production of the standardised activity program were assessed by whole-body indirect calorimetry over 24 hours, and body composition was assessed by dual-energy X-ray absorptiometry. At M9, adolescents showed an 18% reduction in BM (p < 0.001) and 40% in total FM, while fat-free mass (kg) remained stable in boys but decreased by ∼6% in girls (p = 0.001). Similarly, the mean Cw decreased by 20% (p < 0.001). At M13, BM, FM, and Cw were slightly higher compared with at M9. In conclusion, moderate energy restriction and regular moderate physical activities improved walking economy, improved exercise tolerance, and induced beneficial changes in the body composition of adolescents with obesity. Novelty: Reduction of FM in the trunk region, and consequently reducing the work carried out by respiratory muscles, contributes to reducing Cw in adolescents with obesity. A lower walking cost can be effective in improving exercise tolerance and quality of life in obese adolescents.

Adjuvant chemotherapy for stage II colon cancer: influence of care structures' characteristics on a controversial clinical practice.

BACKGROUND: Adjuvant chemotherapy for stage II colon cancer is a controversial practice and is not recommended by the French Consensus Conference outside of therapeutic trial. OBJECTIVE: To assess, within a well-defined population, the influence of hospital characteristics in this practice. PATIENTS AND METHODS: In the Rhône-Alpes region (10% of the French population), 534 patients presenting with colon cancer stage II were operated on in 81 hospitals in the year 2000. The influence of hospital characteristics on the use of adjuvant chemotherapy was assessed using a multivariate logistic regression. RESULTS: Overall, 19.5% of patients received adjuvant chemotherapy. Younger age, T4 tumour, hospital volume lower than 20 colon cancer surgeries [odds ratio (OR) 2.96; P<0.001], formal multidisciplinary input with specific written account (OR 3.25; P=0.001), private funding of the hospital (OR 1.82; P=0.019), and clinical complications at diagnosis were independently associated with higher rates of chemotherapy. On the other hand, a number of examined lymph nodes lower than recommendations did not have any influence on chemotherapy use. CONCLUSION: Hospital characteristics had independently influenced the practice of adjuvant chemotherapy in stage II colon cancer. The more important institutional factor was the hospital procedure volume. The decisions of the multidisciplinary committees appeared at times paradoxical; a more comprehensive evaluation of this practice is needed.

Contributing factors and variability of energy expenditure in non-obese, obese, and post-obese adolescents.

Energy expenditure (EE) is a major determinant of energy balance and body composition. The objectives of this paper were to review the contributing factors of the main components of daily EE (DEE) and the inter-individual variability in these components in non-obese (NOb), obese (Ob), and post-obese (POb) adolescents. Body composition especially fat-free mass (FFM), is the major determinant of the basal metabolic rate which contributes 50-70% of DEE, whereas fat mass (FM) is a significant factor only in obese subjects. Physical activity is the second main variation factor of DEE, whereas growth, the thermic effect of food, and thermoregulation are generally of marginal importance. The energy costs and EE associated with various sedentary and physical activities were assessed in NOb, Ob and POb subjects both in standardised and in free-living conditions. The interindividual variability of DEE is high, even after adjustment for body composition, mainly because of great differences in time devoted to the various physical activities. DEE and EE associated with sleep and sedentary activities are significantly higher in Ob than in NOb, but not after adjustment for FFM. On the contrary, EE associated with physical activities is not significantly different between Ob and NOb adolescents, but 61% lower in Ob subjects after adjustment for body composition. Multidisciplinary weight-reduction programmes including moderate energy restriction and physical training result in great FM loss, maintenance of FFM, improvement of physical capacities, but reductions in organ and tissue metabolic rate and in EE associated with the various sedentary and physical activities, which may favour body weight regain in the less active POb subjects.

Estimating relative physical workload using heart rate monitoring: a validation by whole-body indirect calorimetry.

Measuring physical workload in occupational medicine is fundamental for risk prevention. An indirect measurement of total and relative energy expenditure (EE) from heart rate (HR) is widely used but it has never been validated. The aim of this study was to validate this HR-estimated energy expenditure (HREEE) method against whole-body indirect calorimetry. Twenty-four-hour HR and EE values were recorded continuously in a calorimetric chambers for 52 adult males and females (19-65 years). An 8-h working period was retained, comprising several exercise sessions on a cycloergometer at intensities up to 65% of the peak rate of oxygen uptake. HREEE was calculated with reference to cardiac reserve. A corrected HREEE (CHREEE) was also calculated with a modification to the lowest value of cardiac reserve. Both values were further compared to established methods: the flex-HR method, and the use of a 3rd order polynomial relationship to estimate total and relative EE. No significant difference was found in total EE when measured in a calorimetric chamber or estimated from CHREEE for the working period. A perfect linear and identity relationship was found between CHREEE and energy reserve values for intensities ranging from 15% to 65%. Relative physical workload can be accurately assessed from HR recordings when expressed in CHREEE between 15% to 65%, and EE can be accurately estimated using the CHREEE method.

A weight reduction program preserves fat-free mass but not metabolic rate in obese adolescents.

OBJECTIVE: To determine the effects of a multidisciplinary weight reduction program on body composition and energy expenditure (EE) in severely obese adolescents. RESEARCH METHODS AND PROCEDURES: Twenty-six severely obese adolescents, 12 to 16 years old [mean BMI: 33.9 kg/m(2); 41.5% fat mass (FM)] followed a 9-month weight reduction program including moderate energy restriction and progressive endurance and resistance training. Body composition was assessed by DXA, basal metabolic rate by indirect calorimetry, and EE by whole-body indirect calorimetry with the same activity program over 36-hour periods before starting and 9 months after the weight reduction period. RESULTS: Adolescents gained (least-square mean +/- SE) 2.9 +/- 0.2 cm in height, lost 16.9 +/- 1.3 kg body weight (BW), 15.2 +/- 0.9 kg FM, and 1.8 +/- 0.5 kg fat-free mass (FFM) (p < 0.001). Basal metabolic rate, sleeping, sedentary, and daily EE were 8% to 14% lower 9 months after starting (p < 0.001) and still 6% to 12% lower after adjustment for FFM (p < 0.05). Energy cost of walking decreased by 22% (p < 0.001). The reduction in heart rate during sleep and sedentary activities (-10 to -13 beats/min), and walking (-20 to -25 beats/min) (p < 0.001) resulted from both the decrease in BW and physical training. DISCUSSION: A weight reduction program combining moderate energy restriction and physical training in severely obese adolescents resulted in great BW and FM losses and improvement of cardiovascular fitness but did not prevent the decline in EE even after adjustment for FFM.

Evaluation of two foot-to-foot bioelectrical impedance analysers to assess body composition in overweight and obese adolescents.

The objective of the present study was to determine the accuracy of two foot-to-foot (FF) bioelectrical impedance analysers (BIA) to assess body composition in overweight and obese adolescents, compared with dual-energy X-ray absorptiometry (DXA) and hand-to-foot (HF) BIA. Body composition was assessed in fifty-three overweight or obese adolescents (BMI 27.9 (SD 4.1) kg/m2; aged 13-16 years) by DXA (Hologic QDR-4500; Hologic Inc., Bedford, MA, USA) and BIA (HF (BIA 101, RJL System, Detroit, IL, USA) and FF (Body Fat Monitor Scale BF-625, Tanita Corporation of America Inc., Arlington Heights, IL, USA; Téfal Bodymaster Vision, Téfal, Rumilly, France)). Bland-Altman tests showed that, compared with DXA, FF-Tanita and FF-Téfal underestimated (P<0.05) fat mass (FM) less than HF-BIA (-1.7 (SD 3.1), -0.7 (SD 5.8) and -2.3 (SD 2.2) kg respectively, P<0.001). However, the limits of agreement between DXA and FF-Tanita or FF-Téfal were much greater than those obtained with HF-BIA (-7.7 and +4.3, - 12.0 and +10.6 v. -2.1 and +6.7 kg respectively). The differences between FM assessed using the FF-Tanita or the FF-Téfal analyser and DXA increased with the waist:hip ratio, and were higher in boys than in girls. The major limiting factor of FF-BIA was the inter-individual variability in FM estimates. In conclusion, FF-BIA and DXA are not interchangeable methods. FF-BIA could be acceptable to assess body composition in large groups of overweight or obese adolescents, but cannot be recommended for body composition assessment in obese subjects because of the large errors in individual estimates.

Assessment of energy expenditure associated with physical activities in free-living obese and nonobese adolescents.

BACKGROUND: Information on activity patterns and the energy cost of activities is critically missing. OBJECTIVE: We measured the energy cost of and time devoted to various activities in obese and nonobese adolescents. DESIGN: Daily energy expenditure (DEE) and its main components were determined in 27 obese and 50 nonobese adolescents aged 12-16 y by using whole-body calorimetry with the same activity program and the heart rate-recording method in free-living conditions. RESULTS: In whole-body calorimetry, energy expenditures (EEs) during sleep and sedentary activities were 18.9% and 21.5%, respectively, higher in obese subjects than in nonobese subjects (P < 0.001), but not significantly different after adjustment for fat-free mass (FFM). EEs during walking and DEEs were significantly higher in obese than in nonobese subjects, both absolutely (71% and 33%, respectively) and after adjustment for body weight or FFM (16% and 11%, respectively). In free-living conditions, EEs associated with physical activities did not differ significantly between obese and nonobese subjects, but they were 51% lower in obese subjects after adjustment for body weight (P < 0.001). The obese adolescents spent more time in light physical activities but much less time in moderate activities and sports than did the nonobese subjects. The activity-related time equivalent corrected for sedentary EE (ARTE EE(2)) averaged 69 and 122 min/d in obese and nonobese subjects, respectively (P < 0.01). CONCLUSION: Physical activity is low in obese subjects and can be assessed satisfactorily in both obese and nonobese adolescents by using ARTE EE(2) when DEE and the basal metabolic rate are known.

Prolonged daytime exercise repeated over 4 days increases sleeping heart rate and metabolic rate.

The aim of this study was to determine the influence of prolonged exercise repeated for 4 days on sleeping heart rate (SHR) and metabolic rate (SMR). Eleven young untrained men exercised at moderate intensity 5 hrs daily for 4 days, alternately on a cycle ergometer (57.0 +/- 1.3% .VO2max) and a treadmill (64.7 +/- 1.6% .VO2max). They spent the night prior to the exercise period (control, C) and the 4 nights following exercise days (N1 to N4) in room calorimeters for the measurement of SHR, SMR, and respiratory quotient (RQ) from midnight until 6 a.m. Every morning, before the exercise bouts, plasma-free epinephrine (E) and norepinephrine (NE) levels were measured. After exercise, all SHR values were significantly higher than at C level (52 +/- 1 bpm, p < 0.001) and the highest value was observed on N2 (61 +/- 2 bpm). SMR increased by 11.2 +/- 1.5% from C to N1, p < 0.001, and then plateaued up to N4, whereas RQ decreased from C (0.833 +/- 0.009) to N2 (0.798 +/- 0.005) and then plateaued. Plasma NE levels were higher the morning after each day of exercise and peaked on N2, whereas no significant variations were found for E. Variations of SHR between C and N2, and N3 and N4 were correlated with changes of SMR. No significant relationships were found between morning plasma NE, and either SMR or SHR variations. To conclude, prolonged exercise repeated for 4 days was associated with increases in SHR and SMR during the night following each day of exercise concomitantly with an enhanced lipid oxidation. The sustained stimulation of the sympathetic nervous system may be partly responsible for these effects.

The incorporation of solubilized wheat proteins in milk replacers for veal calves: effects on growth performance and muscle oxidative capacity.

Replacement of skim milk proteins by solubilized wheat protein (SWP) in milk replacers for veal calves would contribute to the reduction in feeding costs. The occurrence of metabolic disorders has, however, been reported. Forty-two male calves received one of three treatments over 140 days: a control diet, a diet containing SWP without or with branched-chain amino acid supplementation. Liveweight gain, carcass yield, color and conformation did not show any significant differences. No metabolic disorders were noted. Supplementation with branched-chain amino acids reduced the marginal Val deficiency but did not modify the growth performances. With the SWP containing diets, the plasma metabolite profile was characteristic of those observed with non-clotting diets. It was statistically correlated to the changes in the orientation of the Semitendinosus muscle energy metabolism towards a more oxidative type and to indications of a lower efficiency of amino acid utilisation for protein deposition. At the present levels of inclusion, SWP proved to be an interesting alternative to the sole use of whey as the protein source in milk replacers for veal calves.

Intraruminal propionate supplementation modifies hindlimb energy metabolism without changing the splanchnic release of glucose in growing lambs.

The influence of propionate supplementation on the splanchnic metabolism of energy-yielding nutrients and the supply of glucose to the hindlimb was investigated in growing lambs. Six rumen-cannulated and multicatheterized lambs (32.2 kg), fed frozen rye grass at 690 kJ metabolizable energy intake/d per kg body weight0.75, were infused intraruminally with a salt solution (control) or with propionate solutions at 0.55 mol/d (P1) or 0.98 mol/d (P2) according to a replicated Latin square design. In the rumen fluid, supplementation decreased the acetate:propionate molar ratio from 2.36:1 to 1.37:1, without modifying the ruminal concentrations of acetate and NH4. As a result, the portal appearance of propionate increased by 51 and 72 % with P1 and P2, respectively, and that of l-lactate doubled. Across the liver, net extraction of propionate increased by 47 and 67 % with P1 and P2, respectively. However, the net hepatic production of glucose remained unchanged, probably as the result of a substantial rise in insulin secretion and its hepatic extraction. Overall, the net splanchnic release of acetate, glucose and butyrate was not modified while that of l-lactate increased. Despite this, the net uptake of acetate, glucose, l-lactate and non-esterified fatty acids by the hindlimb increased. Propionate probably enhanced the storage of energy-yielding nutrients in the hindlimb, despite their unchanged release by the splanchnic tissues and the unmodified insulinaemia. Regulatory mechanisms are not clear.

Two polyol, low digestible carbohydrates improve the apparent absorption of magnesium but not of calcium in healthy young men.

The effects of nondigestible oligosaccharides including polyols on intestinal mineral absorption have been studied extensively in animal experiments, but their impact on mineral absorption in humans remains to be established. We investigated the effects of feeding two fermentable, low digestible carbohydrates, on the apparent absorption and balance of calcium (Ca) and magnesium (Mg) in humans. Nine healthy young men were given a control diet with dextrose or polyols, low digestible, fermentable carbohydrates (LHBC, HPFL) for 32-d periods according to a 3 x 3 Latin-square design. During the 18-d period of adaptation, the products were administered gradually in liquid form, up to a maximum of 100 g/d, which was then consumed for 14 d. Ca and Mg levels were measured in diets and in fecal and urine collections to assess apparent mineral absorption and balance. The relative apparent absorptions of Ca and Mg from the control diet were (means +/- SEM) 33.3 +/- 4.6 and 39.8 +/- 2.7%, respectively. Ingestion of both low digestible carbohydrates significantly increased the relative apparent absorption of Mg by about 25%. LHBC, but not HPFL, ingestion increased urinary Mg excretion. Apparent absorption, urinary excretion and balance of Ca were not altered by the ingestion of either low digestible carbohydrate. Ingestion of the low digestible, fermentable carbohydrates, with balanced diets, improved apparent Mg absorption without significant effects on apparent absorption or retention of Ca in healthy young men. Further human studies are therefore still needed to confirm the effects of these products in other populations.

Propionate supplementation did not increase whole body glucose turnover in growing lambs fed rye grass.

The objective of the present study was to investigate the effects of propionate supplementation on whole body glucose turnover in growing lambs fed frozen rye-grass at 1.5 x maintenance using [1-13C]-glucose. Intraruminal infusion of propionate (0.55 and 0.91 mol x d(-1)) increased the ruminal molar proportions of propionate from 25% with the control to 40% with the highest propionate treatment. It did not however modify glucose turnover (26 mmol x d(-1) x kg(-1)), nor the conversion of its carbon into L-lactate (21%) and alanine (21%), nor glucose recycling (9%). All of the results suggest that in the present conditions glucose turnover and metabolism were not influenced by the supply of propionate.