The effectiveness of multidisciplinary weight loss interventions is associated with initial cardiorespiratory fitness in adolescents with obesity.

BACKGROUND: The identification of predictive parameters of the success of multidisciplinary weight loss interventions (MWLI) appears essential to optimize obesity management. The association between baseline cardiorespiratory fitness (CRF) and changes in anthropometric parameters and body composition during MWLI remains underexplored in adolescents with obesity. OBJECTIVES: To assess whether baseline CRF was associated with the effectiveness of a 16-week MWLI measured through improved body mass, body mass index (BMI) and body composition (percentage of total fat mass (FM) as the main criterion). METHODS: Cardiorespiratory fitness and body composition were respectively measured by peak oxygen consumption (VO2peak) during maximal exercise tests and dual-photon x-ray absorptiometry (DXA), before (T0) and after (T1) a 16-week MWLI in 165 adolescents (aged 13.3 ± 1.38 years, 61.2% female, BMI 35.11 ± 5.16 kg/m2). RESULTS: Reductions in BMI and total FM percentage between T0 and T1 were greater in subjects with a baseline VO2peak ≥ 3rd quartile compared to the first quartile (p < 0.001) and the interquartile range (p < 0.05 and p < 0.001, respectively). Baseline VO2peak and VO2 at the first ventilator threshold were positively correlated with the reductions in body mass, BMI and total and visceral FM percentages and with the increase in lean mass (LM) percentage between T0 and T1 after adjustment for age and gender (p < 0.001). CONCLUSION: Initial CRF is associated with the success of MWLI in adolescents with obesity. Improving their aerobic fitness before starting a MWLI might be a promising strategy to optimize its benefits.

The association between obesity severity and food reward in adolescents with obesity: a one-stage individual participant data meta-analysis.

BACKGROUND: Food reward and cue reactivity have been linked prospectively to problematic eating behaviours and excess weight gain in adults and children. However, evidence to date in support of an association between degree of adiposity and food reward is tenuous. A non-linear relationship between reward sensitivity and obesity degree has been previously proposed, suggesting a peak is reached in mild obesity and decreases in more severe obesity in a quadratic fashion. OBJECTIVE: To investigate and characterise in detail the relationship between obesity severity, body composition, and explicit and implicit food reward in adolescents with obesity. METHODS: Data from seven clinical trials in adolescents with obesity were aggregated and analysed in an independent participant data meta-analysis. Linear and curvilinear relationships between the degree of obesity and explicit and implicit reward for sweet and high fat foods were tested in fasted and fed states with BMI-z score as a continuous and discrete predictor using clinically recognised partitions. RESULTS: Although positive associations between obesity severity and preference for high-fat (i.e. energy dense) foods were observed when fasted, none reached significance in either analysis. Conversely, adiposity was reliably associated with lower reward for sweet, particularly when measured as implicit wanting (p = 0.012, ηp2 = 0.06), independent of metabolic state. However, this significant association was only observed in the linear model. Fat distribution was consistently associated with explicit and implicit preference for high-fat foods. CONCLUSIONS: A limited relationship was demonstrated between obesity severity and food reward in adolescents, although a lower preference for sweet could be a signal of severe obesity in a linear trend. Obesity is likely a heterogenous condition associated with multiple potential phenotypes, which metrics of body composition may help define. CLINICAL TRIAL REGISTRATIONS: NCT02925572: https://classic. CLINICALTRIALS: gov/ct2/show/NCT02925572 . NCT03807609: https://classic. CLINICALTRIALS: gov/ct2/show/NCT03807609 . NCT03742622: https://classic. CLINICALTRIALS: gov/ct2/show/NCT03742622 . NCT03967782: https://classic. CLINICALTRIALS: gov/ct2/show/NCT03967782 . NCT03968458: https://classic. CLINICALTRIALS: gov/ct2/show/NCT03968458 . NCT04739189: https://classic. CLINICALTRIALS: gov/ct2/show/NCT04739189 . NCT05365685: https://www. CLINICALTRIALS: gov/study/NCT05365685?tab=history .

Development of the Children and Adolescents Physical Activity and Sedentary Questionnaire (CAPAS-Q): Psychometric Validity and Clinical Interpretation.

BACKGROUND: Pediatricians' clinical practice and health interventions in youths require instruments with adequate psychometric properties to assess physical activity (PA), sedentary behaviors (SB), and their subdomains. OBJECTIVE: To assess the psychometric properties of the Children and Adolescents Physical Activity and Sedentary-Questionnaire (CAPAS-Q) in healthy French children and adolescents. METHODS: The CAPAS-Q has been developed through a rigorous collective procedure and consists of a 31 items self-administered questionnaire evaluating children's 7-day PA and SB dimensions and subdomains. Participants (n = 103, aged 8-18 years old) completed the questionnaire twice (7 days apart) and wore an ActiGraph GT3X + accelerometer for 7 days. Anthropometric measurements and body composition were assessed. RESULTS: Cronbach alpha for PA and SB dimensions were 0.71 and 0.68, respectively. Reproducibility was found moderate to good, with Lin's coefficients of 0.69 and 0.68 for PA and SB dimensions, respectively. Reproducibility was higher for adolescents compared to children. PA dimension was positively correlated with moderate PA, vigorous PA, moderate to vigorous PA, and total PA times and negatively correlated with SB time (p < 0.05). SB dimension and screen time were positively correlated with SB time and negatively correlated with LPA, MPA, MVPA, and total PA times (p < 0.05). Spearman correlation coefficients were fair to moderate, ranging between 0.23-0.45. CONCLUSION: The CAPAS-Q proposes a reliable and valid evaluation of French children and adolescents' PA and SB, providing clinicians with potential intervention levels to improve youth movement behaviors.

Patterns of body weight change affect weight loss during a multidisciplinary intervention in adolescents with obesity.

AIM: The current pediatric obesity health challenge necessitates a better understanding of the factors affecting weight loss success during interventions. The aim of this observational study was to test the impact of the rate of initial weight loss and body weight variability on weight loss during a 9-month residential, multidisciplinary weight loss program in adolescents with obesity. METHODS: This retrospective study considered a whole sample of 510 adolescents with obesity (12-16 years, 435 girls). Body weight assessment was performed before (T0) and each week during the 9 months of a multidisciplinary weight loss program. Initial weight change (week 4-W4) and overall weight change at week 12 (T1) and the end of the intervention (T2) were considered. Participants were divided into three groups (tertiles), based on their percentage of weight loss between T0 and W4; and weight variability was expressed by the root mean square error (RMSE) around each participant's regression line at each considered period (W4, T1, T2). RESULTS: Adolescents with lower initial weight loss at W4 (tertile 3) displayed the lesser weight loss at T1 and T2 compared with adolescents in tertile 1 and 2. The RMSE was positively associated with the percentage of weight loss of the period considered, but when the analyses were adjusted for age and initial body weight, there was no more significant association. CONCLUSIONS: The rate of weight loss during the first few weeks is crucial for weight loss success, and weight variability is positively associated with weight loss in adolescents with obesity. Overall, results show that initial body weight is a determinant characteristic to consider during a lifestyle intervention. Further studies are thus needed to better understand the relationship between body weight change patterns and weight loss during the dynamic state that is adolescence.

Designing, Implementing, and Evaluating a Home-Based, Multidisciplinary, Family-Centered Pediatric Obesity Intervention: The ProxOb Program.

Although family-based interventions have been suggested as promising approaches for preventing and treating pediatric obesity, available studies failed to include the whole family in its own natural environment and routine. This paper aims to detail the development, implementation, and evaluation phases of the ProxOb home-based, family-centered program and present its feasibility and early results. ProxOb provides families with a 6-month multidisciplinary, home-based, and family-centered intervention followed by an 18-month maintenance phase. A global psychosocial, clinical, and behavior evaluation was conducted at baseline (T0) at the end of the 6-month intervention (T1) and after the 18-month maintenance phase (T2). A total of 130 families with at least one child with obesity completed the ProxOb program so far, and more than 90% of them also presented at least one parent with overweight or obesity. Being part of a single-parent family seemed to increase the chance of completing the intervention (63.0% vs. 33.3% in the drop-outers subgroup, p = 0.03). The BMI z-score for children with obesity (T0 = 4.38 ± 1.05; T1 = 4.06 ± 1.07; T2 = 4.29 ± 1.12) significantly decreased between T0 and T1, followed by weight regain at T2. ProxOb proposes a feasible and replicable real-life approach to address childhood obesity while involving the children's family.

Does exercising before or after a meal affect energy balance in adolescents with obesity?

BACKGROUND AND AIM: Exercise timing has been suggested to affect appetite and energy intake (EI). The aim of this study was to examine the impact of exercising immediately before or after a meal on EI, appetite sensations and food reward (FR) in adolescents with obesity. METHODS AND RESULTS: Seventeen adolescents with obesity completed 3 experimental sessions (randomized controlled trial): rest + lunch (CON); exercise + lunch (EX-MEAL); lunch + exercise (MEAL-EX). The exercise consisted of cycling 30 min at 65%V̇O2peak. Outcomes included ad libitum EI (weighed lunch and dinner), FR (Leeds Food Preference Questionnaire at pre- and post-combination of exercise/rest and lunch, and pre-dinner) and appetite sensations (visual analogue scales). EI was not different between conditions. Compared with CON, relative EI at lunch was lower in EX-MEAL and MEAL-EX (p ≤ 0.05) and daily only in MEAL-EX (p < 0.01). Postprandial fullness was higher in EX-MEAL compared to CON. Compared with CON, both EX-MEAL and MEAL-EX attenuated the increase in wanting for sweet food and reduced explicit liking for fat. CONCLUSIONS: These preliminary results suggest that exercising immediately before or after a meal produce few differences in appetite and have small beneficial effects on overall energy balance in adolescents with obesity, as well as on FR. CLINICAL TRIALS: NCT03967782.

Effect of a 10-month residential multidisciplinary weight loss intervention on food reward in adolescents with obesity.

BACKGROUND: While multidisciplinary weight loss (WL) programs have been suggested to improve the sensitivity of appetite control system, this study examined for the first time the effect of a specific multidisciplinary intervention on the hedonic aspects of food intake in adolescents with obesity. STUDY DESIGN: Twenty-four adolescents (11-15 years) with obesity (mean BMI: 35.7 ±â€¯4.5 kg/m2; BMI percentile: 98.7 ±â€¯0.5) took part in a 10-month inpatient WL program, which included physical activity, nutritional education and psychological support. Height, weight, body composition, food reward (pre- and post-meal), ad libitum energy intake, appetite sensations and eating behavior traits were assessed at baseline, 5 months and at the end of the 10-month intervention. Analyses were conducted with linear mixed models and paired t-tests. RESULTS: The mean WL was 8.9 ±â€¯6.9 kg. Appetite sensations and pre-meal hedonic ratings of liking for all food categories (HF: high-fat; LF: low-fat; SA: savory; SW: sweet) increased after 5 months (fasting hunger, p = 0.02; fasting desire to eat, p = 0.01; daily hunger, p = 0.001; pre-meal liking for HFSA, p = 0.03; LFSA, p = 0.04; HFSW, p = 0.009; LFSW, p = 0.005). In contrast, appetite sensations (fasting and daily), emotional eating (p < 0.001), uncontrolled eating (p = 0.009), and pre-meal explicit liking (for all food categories) decreased between months 5 and 10. Post-meal liking for HFSA (p < 0.001), LFSA (p = 0.002), HFSW (p = 0.02) and LFSW (p < 0.001) decreased between baseline and month 5 and remained unchanged between months 5 and 10. CONCLUSION: These findings suggest that adaptive mechanisms to WL occurring in the short-to-medium term are attenuated in the longer term with the persistence of WL. These results indicate improvements in the reward response to food in adolescents with obesity and may contribute to the beneficial effect of multicomponent WL interventions in this population. Future studies are required to confirm these findings and elucidate underlying mechanisms.

Delayed meal timing after exercise is associated with reduced appetite and energy intake in adolescents with obesity.

BACKGROUND: While the beneficial effects of exercise on appetite might depend on its timing during the day or relative to a meal, this remains poorly explored in youth. OBJECTIVES: To examine the importance of meal timing (+30 vs +90 minutes) after performing exercise on energy intake, appetite and food reward in adolescents with obesity. METHODS: Eighteen adolescents with obesity randomly completed three conditions: (a) lunch (12:00 pm) set 30 minutes after a rest session (11:00 am); (b) lunch (12:00 pm) set 30 minutes after an exercise session (11:00 am)(MEAL-30); (c) lunch (01:00 pm) set 90 minutes after an exercise session (11:00 am)(MEAL-90). Lunch and dinner ad libitum energy intake was assessed, food reward (LFPQ) assessed before and after lunch, and before dinner, appetite sensations were assessed at regular intervals. RESULTS: Energy intake was lower at MEAL-90 than MEAL-30 and CON at lunch (P < .05 and P < .01, respectively) and lunch + dinner combined (P < .001). A decrease in intake (g) of protein, fat and carbohydrate was observed. Post-exercise hunger was lower on MEAL-90 compared with CON. No condition effects were found at lunch for food reward. CONCLUSIONS: Delaying the timing of the meal after exercise might help affect energy balance by decreasing ad libitum energy intake without increasing hunger and by improving satiety in adolescents with obesity.

Is the SPARTACUS 15-15 test an accurate proxy for the assessment and tracking of maximal aerobic capacities in adolescents with obesity?

[Purpose] While there is a need for reliable field tests for the evaluation of physical fitness in pediatric obesity, the present work i) evaluates the validity of the Spartacus 15-15 test in indirectly assessing maximal aerobic capacity in adolescents with obesity and ii) evaluates its sensibility to weight loss. [Participants and Methods] Fifty-five 11-16 year-old adolescents with obesity (Tanner 3-4) were enrolled in a 12-week weight-management intervention. Maximal Aerobic fitness (VO2peak test + Spartacus test) and body composition (Dual X-ray absorptiometry) were assessed at baseline and after 12 weeks. [Results] Moderate correlations were found at baseline between VO2peak (2,231.90 ± 465.6 mL/min) and Spartacus stage (6.83 ± 1.8 stage, r=0.52; p≤0.05), speed (12.85 ± 1.8 km/h, r=0.52 ; p≤0.05) and time (20.6 ± 5.4 min; r=0.50; p≤0.05). The intervention favored significant improvements for VO2peak, Spartacus Rate of Perceived Exertion final stage, maximal speed and time. Change over time in VO2peak and Spartacus variables were not correlated. [Conclusion] The Spartacus test can be used as a proxy for VO2peak at baseline and can be used to estimate VO2peak using the proposed equation. The Spartacus 15-15 test might be a better indicator for changes in functional capacity than an indicator of VO2peak changes in youth with obesity.

Sleep-disordered breathing in adolescents with obesity: When does it start to affect cardiometabolic health?

BACKGROUND AND AIMS: Pediatric obesity and sleep-disordered breathing (SDB) are associated with cardiometabolic risk (CMR), but the degree of severity at which SDB affects cardiometabolic health is unknown. We assessed the relationship between the CMR and the apnea-hypopnea index (AHI), to identify a threshold of AHI from which an increase in the CMR is observed, in adolescents with obesity. We also compared the clinical, cardiometabolic and sleep characteristics between adolescents presenting a high (CMR+) and low CMR (CMR-), according to the threshold of AHI. METHODS AND RESULTS: 114 adolescents with obesity were recruited from three institutions specialized in obesity management. Sleep and SDB as assessed by polysomnography, anthropometric parameters, fat mass (FM), glucose and lipid profiles, and blood pressure (BP) were measured at admission. Continuous (MetScoreFM) and dichotomous (metabolic syndrome, MetS) CMR were determined. Associations between MetScoreFM and AHI adjusted for BMI, sex and age were assessed by multivariable analyses. Data of 82 adolescents were analyzed. Multivariable analyses enabled us to identify a threshold of AHI = 2 above which we observed a strong and significant association between CMR and AHI (Cohen's d effect-size = 0.57 [0.11; 1.02] p = 0.02). Adolescents with CMR+ exhibited higher MetScoreFM (p < 0.05), insulin resistance (p < 0.05), systolic BP (p < 0.001), sleep fragmentation (p < 0.01) and intermittent hypoxia than CMR- group (p < 0.0001). MetS was found in 90.9% of adolescents with CMR+, versus 69.4% in the CMR- group (p < 0.05). CONCLUSIONS: The identification of a threshold of AHI ≥ 2 corresponding to the cardiometabolic alterations highlights the need for the early management of SDB and obesity in adolescents, to prevent cardiometabolic diseases. CLINICAL TRIALS: NCT03466359, NCT02588469 and NCT01358773.

Are obstructive sleep apnea and sleep improved in response to multidisciplinary weight loss interventions in youth with obesity? A systematic review and meta-analysis.

BACKGROUND: Pediatric obesity is closely associated with obstructive sleep apnea (OSA) and short sleep duration. While multidisciplinary weight loss interventions are recommended for pediatric obesity management, the evidence for their effects on OSA severity and overall sleep in youth have not been systematically examined. OBJECTIVES: To conduct a systematic review and meta-analysis investigating the effects of multidisciplinary weight loss interventions on OSA severity and prevalence, and on overall sleep health in youth with obesity. METHODS: A systematic search of interventional studies (participants age range: 10-19 yrs) was performed using PubMed, CENTRAL and Embase, from inception to May 2019. The quality of the evidence was assessed using the Cochrane risk of bias tool. RESULTS: Ten studies were included by the end of the screening process. Ninety percent of the included studies reported a decrease in OSA prevalence post-intervention, and OSA was normalized for 46.2-79.7% of the youth. The meta-analysis comprising seven longitudinal studies revealed significant reductions in apnea-hypopnea index (effect size: -0.51, 95%CI -0.94 to -0.08, p = 0.019), and oxygen desaturation index (effect size: -0.28, 95%CI = -0.50 to -0.05, p = 0.016). Seventy-five percent of the studies reported improved sleep duration in youth with OSA. CONCLUSIONS: Evidence suggests that multidisciplinary weight loss interventions result in improvements in OSA severity and sleep duration in youth with obesity. Future randomized controlled trials are warranted to better assess and understand the independent implications of weight loss, fat mass decrease and chronic exercise on OSA and sleep health in this population.

Geometric and Mechanical Bone Response to a Multidisciplinary Weight Loss Intervention in Adolescents With Obesity: The ADIBOX Study.

The effectiveness of structured multidisciplinary weight loss (WL) programs combining nutrition and physical activity on bone geometry and strength remains uncertain in adolescents with obesity. The study investigated the impact of a structured WL intervention on bone geometry and strength in adolescents with obesity. Thirty-one adolescents with obesity (mean [standard deviation] 13.61 [1.27] yr, body mass index Z-score 2.26 [0.30]) experienced an 8-mo WL program. A group of 23 maturation-matched controls (mean [standard deviation] 15.90 [0.43] yr, body mass index Z-score -0.12 [0.48]) were recruited for calculating Z-scores. Body composition, bone density, geometry, and mechanical properties were assessed using dual-energy X-ray absorptiometry and dual-energy X-ray absorptiometry-derived hip structural analysis. Plasma concentration of leptin, estradiol, collagen type 1 cross-linked C-telopeptide (CTx), and procollagen type 1 N-terminal propeptide were measured. Longitudinal analysis showed that adolescents with obesity reduced body weight and fat mass (total [g, %; p < 0.007]). After 8 mo, body mineral density at total body less head (Δ 3.22 [3.58] % p < 0.001) and lumbar spine (Δ 3.67 [4.04] % p < 0.001) increased. At the narrow neck (NN) of the femur, lower body mineral density (Δ -7.19 [8.79] % p < 0.001) and higher endocortical diameter and width were observed (NN endocortical diameter Δ 2.85 [0.26] %, NN width Δ 5.48 [10.84] %, respectively). An increased buckling ratio (Δ 8.24 [2.00] % p = 0.005) was also evident. Similar concentration of procollagen type 1 N-terminal propeptide and CTx was seen from baseline to 8 mo. However, at 4 mo, lower CTx levels were observed. The 8-mo WL program was associated with some positive adaptations among bone density parameters for the whole body and spine. However, bone geometry and strength estimates appeared to weaken at the NN. Clinically, the buckling ratio score at the NN was close to the fracture threshold. An "androgynous-like" adaptation was observed with bone geometry changes demonstrating periosteal expansion and endocortical resorption.

Usefulness of the satiety quotient in a clinical pediatric obesity context.

BACKGROUND: While the satiety quotient (SQ) is increasingly used in pediatric populations, the present study assessed its reliability and reproducibility in adolescents with obesity. METHODS: Sixty-eight adolescents with obesity were enrolled. Anthropometric measurements and body composition (DXA) were assessed. They randomly completed two experimental sessions: (i) condition with a standardized breakfast used to calculate SQ (C1); (ii) condition with the same breakfast and ad libitum lunch and dinner buffet meals (C2). Appetite feelings were assessed at regular interval (visual analog scales). RESULTS: SQ for hunger (SQH), satiety (SQS), prospective food consumption (SQP), and desire to eat (SQD) were calculated using the breakfast. SQH, SQD, and SQ mean did not differ between conditions (p = 0.41, 0.57, and 0.74, respectively) whereas SQS and SQP were significantly different between conditions (p = 0.007 and 0.005). None of the SQ was correlated with body weight (BW), BMI, or FM. There was no significant correlation between the SQ and the adolescent's ad libitum energy intake (lunch, dinner, and total). No differences were observed between adolescents with a low and high phenotype for BW, BMI, and FM% (p = 0.26, 0.30, and 0.83); total energy (p = 0.21); total protein intake (p = 0.28); total fat intake (p = 0.24) and total carbohydrate intake (p = 0.44). Thirty percent of the adolescents showed different satiety phenotype (low vs. high) between C1 and C2. CONCLUSIONS: While the SQ is a reliable indicator in adults, it must be used with caution in adolescents with obesity due to its lack of association with anthropometric measurements, body composition, and energy and macronutrient intakes in this population.

Health-related quality of life and perceived health status of adolescents with obesity are improved by a 10-month multidisciplinary intervention.

BACKGROUND: Although multidisciplinary weight management interventions have been shown effective in improving body composition and cardio-respiratory fitness, their effects on HRQOL and perceived health status remain uncertain in adolescents with obesity. OBJECTIVE: To assess the impact of a 10-month multidisciplinary weight management intervention on HRQOL and health perception in adolescents with obesity, exploring whether these changes were associated with changes in body weight and body composition. METHODS: Thirty-six adolescents with obesity (28 girls and 8 boys; mean age: 13 ±â€¯1.32 years) enrolled in a multidisciplinary weight management intervention composed of nutritional counseling, physical activity and health-related therapeutic education. Validated self-report questionnaires were used to assess HRQOL (SF-36) and health perception (HP questionnaire) at baseline (T0) after5 months (T1) and after 10 month of intervention (T2). In addition, anthropometric parameters and body composition (DXA) were measured at T0, T1 and T2. RESULTS: Items of the SF-36 significantly improved at T1 and T2, such as physical functioning (P < .01), general health (P < .01), physical (P < .001) and mental score (T1: P < .05, T2: P < .01). Dimensions of health perception improved significantly such as physical condition (P < .01 at T2), adiposity (P < .001 at T1 and T2), healthy balanced diet (P < .01 at T1 and P < .001 at T2), general health (P < .05), and perceived general health (T1: P < .01, T2: P < .001). Body weight, BMI, and fat mass (in Kg and in %) were significantly decreased (P < .001) at T1 and T2. No relationship was observed between variations of weight, BMI and Fat mass and variations of HRQOL and health perception. CONCLUSION: A 10-month multidisciplinary weight-management intervention was associated with positive changes in HRQOL and perceived health status, which might not be explained by body weight and adiposity improvements.

High-intensity interval training in overweight and obese children and adolescents: systematic review and meta-analysis.

INTRODUCTION: While High Intensity Interval Training is praised in many populations for its beneficial effects on body composition and cardiometabolic health, its use among obese youth remain uncertain. This study aimed at determining whether HIIT is effective to improve aerobic fitness and reduce cardiometabolic risk factors in overweight and obese youth. EVIDENCE ACQUISITION: A systematic search was conducted and articles reporting studies that investigated the effects of HIIT in 6 to 18-year-old youth were eligible. Meta-analyses were performed when appropriate. EVIDENCE SYNTHESIS: Fifteen studies were included for the systematic review and meta-analyses. HIIT significantly improves maximal oxygen uptake (1.117 [95% CI: 0.528 to 1.706], P<0.001), and reduces body mass (-0.295 [95% CI: -0.525 to -0.066], P<0.05), body fat (-0.786 [95% CI: -1.452 to -0.120], P<0.05), systolic and diastolic blood pressure (-1.026 [95% CI: -1.370 to -0.683], P<0.001; -0.966 [95% CI: -1.628 to -0.304], P<0.01 respectively), and the HOMA-IR (-1.589 [95% CI: -2.528 to -0.650], P<0.01). However, there is significant heterogeneity, and low to high inconsistency for most cardiometabolic risk factors and aerobic fitness. CONCLUSIONS: Although few studies have reported cardiometabolic risks, HIIT may also be as effective as traditional endurance continuous training to decrease blood pressure and insulin resistance. HIIT is effective to improve aerobic fitness, body composition, and cardiometabolic risk factors in obese youth, but data are insufficient to determine whether it is more effective than traditional continuous submaximal intensity exercise training.

The accuracy of bioelectrical impedance to track body composition changes depends on the degree of obesity in adolescents with obesity.

The aim of the present study was to assess the sensitivity of bio-impedance (BIA) in tracking body composition changes in adolescents with various degrees of obesity. We hypothesized that while BIA provides a reliable measure of body composition, its accuracy decreases with increasing obesity and its ability to track changes might be reduced with higher degree of body weight and body composition. Whole-body and segmental body composition were assessed by bio-impedance analysis (BIA-Tanita MC-780) and dual x-ray absorptiometry (DXA, Hologic) among 196 obese adolescents (Tanner stage 3-5) aged 14 ±â€¯0.9 years old, before and after a 3-month weight loss program. Except for the measurement of FFM (kg) (r = 0.03; P = .721; ρ = 0.107; P = .246), the percentage of variation between M0 and M3 for FM% (r = 0.41, P < .001; ρ = 0.534; P < .001) and FMkg (r = 0.64 P < .001; ρ = 0.572; P < .001) are significantly correlated and show significant concordance between DXA and BIA. FMkg and FM% changes between M0 and M3 are similarly tracked by DXA and BIA whatever the initial degree of obesity (based on initial weight, BMI, FM% and FFMkg tertiles). The higher the degree of changes and the higher are the differences between the two devices in measuring FM% and FMkg changes. We found inconsistent and low correlations and concordances between the two devices when tracking FM% changes whatever the degree of weight and FM (kg and %) variations. The accuracy of body composition assessment using BIA decreases with increasing obesity, and its reliability to track changes is reduced with high initial or variations of body weight, FM, FFM and BMI.

Effect of Exercise Duration on Subsequent Appetite and Energy Intake in Obese Adolescent Girls.

There is a growing interest regarding the effect of exercise on appetite and energy intake in youth. While the role of exercise intensity has been a primary focus of study, the effect of exercise duration on subsequent food intake has not been fully examined in obese adolescents. On three separate mornings in a randomly assigned order, obese adolescent girls (n = 20) aged 12-15 years old were asked to perform a rest session (control, CON) or two cycling sessions for 20 (EX20) or 40 min (EX40) set at their ventilatory threshold. Absolute and relative energy intake were measured from an ad libitum lunch meal 30 min after rest or exercise and appetite feelings assessed using visual analogue scales throughout the day. Hunger, satiety, and prospective food consumption were not significantly different between conditions. Absolute energy intake (kcal) did not differ between conditions, while relative energy intake on EX40 (571 ± 381 kcal) was significantly lower than during CON (702 ± 320 kcal; p < .05) and EX20 (736 ± 457 kcal; p < .05). Fat ingestion (in grams) was significantly lower on CON (7.8 ± 3.2 g) compared with EX20 (10.3 ± 4.6 g; p < .01). Protein intake (in grams) was higher on EX20 (37.0 ± 16.6 g) compared with both CON (29.5 ± 11.7 g; p < .01) and EX40 (33.1 ± 10.9 g; p < .05). However, the percentage of total energy derived from each macronutrient was not different between conditions. Obese adolescent girls do not compensate for an acute bout of exercise set at their ventilatory threshold by increasing energy intake, regardless of the exercise duration.