Higher energy flux may improve short-term appetite control in adolescents with obesity: the NEXT study.

Recent evidence suggests better appetite control in states of high-energy flux (HEF) in adults and lean children. Nevertheless, it is unknown whether this extends to youth with obesity. This study compares the effects of low, moderate or HEF on short-term appetitive control in adolescents with obesity. Sixteen adolescents with obesity (12-16 years, Tanner stages 3-5, 11 females) randomly completed three conditions: (i) low-energy flux (LEF); (ii) moderate energy flux (MEF; + 250 kcal) and (iii) HEF (HEF; + 500 kcal). Energy flux was achieved in MEF and HEF through elevated energy intake (EI) and concomitant increase in energy expenditure using cycling exercise (65 % VO2peak). Ad libitum EI, macronutrient intake and relative EI were assessed at dinner, subjective appetite sensations taken at regular intervals and food reward measured before dinner. Ad libitum EI at dinner was greater in LEF compared with HEF (P = 0·008), and relative EI (REI) was higher in LEF compared with MEF (P = 0·003) and HEF (P < 0·001). The absolute consumption of carbohydrates was lower in LEF compared with MEF (P = 0·047) and HEF (P < 0·001). Total AUC for hunger and desire to eat was lower in HEF compared with LEF (P < 0·001) and MEF (P = 0·038). Total AUC for prospective food consumption was lower on HEF compared with LEF (P = 0·004). Food choice sweet bias was higher in HEF (P = 0·005) compared with LEF. To conclude, increasing energy flux may improve short-term appetite control in adolescents with obesity.

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 .

Cardiorespiratory fitness has declined among French children since 1999, although the decline appears to be getting smaller.

BACKGROUND: Cardiorespiratory fitness (CRF) is a strong marker of current and future health. The aim of this study was to assess the national temporal trends in CRF for French children and adolescents between 1999 and 2022. METHODS: CRF data were obtained from several cross-sectional studies on 15 420 (51.1% boys) French children and adolescents aged 9-16 years between 1999 and 2022. The 20-m shuttle run test (20mSRT) estimated CRF. Body mass index (BMI) was calculated from measured height and body mass, with BMI z-scores (BMIz) calculated using WHO growth curves. The 20mSRT results were corrected for protocol and converted to z-scores (20mSRTz) using international sex- and age-specific norms. With additional adjustment for BMIz, temporal trends in mean 20mSRT performance (20mSRTz) were estimated using linear regression, with the distance max (Dmax) method used to locate a breakpoint and linear segments fitted to points below and above the breakpoint. Trends in distributional characteristics were assessed visually and described as the ratio of the coefficients of variation (CVs). RESULTS: After adjustment for protocol, age, sex, and BMIz, a large decline in mean 20mSRT performance (trend per decade (95% CI): -1.42 SDs (-1.45, -1.39) or -18.4% (95% CI: -18.8, -18.0)) between 1999 and 2022 was found. Dmax located a breakpoint for the two-linear-segment model in year 2010. There was a large decline in mean 20mSRT performance pre-2010 (trend per decade (95% CI): -2.31 SDs (-2.39, -2.24)), which reduced 0.06-fold to a negligible decline post-2010 (trend per decade (95% CI): -0.15 SD (-0.20, -0.10)). We also found that the trend in mean 20mSRT performance was not uniform across the population distribution. Between 1999 and 2022, there was a small trend in distributional asymmetry, with slightly smaller declines experienced by the high performers (above the 75th percentile). CONCLUSIONS: Our data suggest a large decline in the 20mSRT performance of French children and adolescents since 1999. This declining trend seems to have diminished considerably since 2010. Such declines in CRF could translate into declines in health status. Although a slowing in the declining trend in CRF in recent years is encouraging, more data are needed to confirm these findings.

A smartphone application as a personalized treatment tool for adolescents with overweight: an explorative qualitative study.

BACKGROUND: The present study is the first step of a 3-year European project in which a tailored smartphone application will be developed and tested as a potential tool in the personalized treatment of children and adolescents with overweight. METHODS: In this study, 10 focus groups (n = 48 participants) were conducted in Belgium, The Netherlands and France with adolescents with overweight (12-16 years; n = 30) and parents of adolescents with overweight (n = 18) to investigate their perceptions on (un)healthy behavior, the drivers of these behaviors, and the needs of an eHealth application for weight loss. A thorough thematic analysis was performed using Nvivo12. RESULTS: Results show that adolescents with overweight have a well-articulated perspective on (un)healthy behavior and their needs. Parents underestimate their own influence on the (un)healthy behavior of their children and report difficulties in healthy lifestyle parenting, which makes their role as a coach rather ambiguous. Concerning the needs of an eHealth application, both parents and adolescents formulated some challenging expectations regarding the content and the format including information, a monitoring feature and features that increase participants' motivation to behave healthy. The results of this analysis will form the basis for designing a personalized eHealth application, which will be tested in a next phase. CONCLUSION: We can conclude that adolescents have a well-articulated perspective on healthy and unhealthy behavior and their needs, whereby a new app could be of great help. It could function as a day-by-day diary and as a supportive coach.

The energy content of meals with a similar macronutrient distribution may have a greater impact on appetite sensations than food preferences in adolescents with obesity: A secondary analysis.

PURPOSE: The energy and macronutrient composition of a meal has been shown to influence postprandial appetitive responses, but it is not clear how energy content independent of macronutrient distribution affects postprandial appetite in adolescents with obesity. Extracting data from a primary study testing the effect of energy turnover on appetite, this secondary analysis assessed how fixed meals varying in energy content with similar macronutrient distributions influences postprandial appetite sensations and food reward. METHODS: Using a randomised, counterbalanced crossover design, N = 14 adolescents with obesity (Mage = 12.71, SDage = 0.99; 10 female) consumed fixed lunch meals with similar macronutrient content starting at 750 kcal in energy and progressively increasing by 250 kcal on three different test days. Liking and wanting for food images varying in fat and taste were assessed at baseline and immediately after meal consumption. Appetite sensations were assessed in half-hour intervals from baseline to 1-h post-meal. RESULTS: The area under the curve for subjective hunger (p < .001, ω = 0.36), desire to eat (p < .001, ω = 0.54), and prospective food consumption (p = .004, ω = 0.32) were significantly lower after consumption of the higher calorie meals relative to the lowest. Explicit wanting for sweet foods increased after intake of the intermediate calorie meal yet decreased after the highest calorie meal (p = .014, ω = 0.09). Conversely, implicit wanting sweet bias increased after consumption of the test meal independent of energy content (p < .001, ω = 0.15). CONCLUSION: The consumption of additional calories without a meaningful change in macronutrient distribution may affect appetite sensations more reliably than hedonic responses to energy-dense foods in adolescents with obesity.

Dietary- but not exercise-induced acute iso-energetic deficit result in short-term appetitive compensatory responses in adolescents with obesity.

BACKGROUND: Producing negative energy balance rests on the creation of energy deficits that have been shown, depending on their modality, to induce potential appetitive compensatory responses. The aim of this study was to compare energy intake (EI), appetite feelings, and the hedonic responses to equivalent acute energy deficits induced by exercise versus energy restriction in adolescents with obesity. METHODS: In a within-participants design, seventeen adolescents with obesity (12-16 years, Tanner stage 3-5, 9 males) randomly completed three conditions: i) control (CON); ii) deficit induced by diet only (Def-EI); and iii) deficit induced by exercise only (Def-EX). Lunch was calibrated to generate a 400-kcal deficit in Def-EI and remained similar in CON and Def-EX. A 400-kcal deficit was created through a cycling bout set at 65% VO2peak in Def-EX. Ad libitum EI, macronutrient intake and relative EI (REI) were assessed at dinner, subjective appetite sensations taken at regular intervals, and food reward measured before dinner. RESULTS: Food intake at dinner was greater in Def-EI (1112 ± 265 kcal) compared to CON (983 ± 277 kcal; p = 0.005) and Def-EX (1009 ± 281 kcal; p = 0.025). Absolute protein and lipid intake were significantly higher in Def-EI (52.4 ± 9.5 g and 36.8 ± 8.9 g respectively) compared with both CON (44.9 ± 12.6 g; p = 0.001 and 33.8 ± 10.1 g; p = 0.002 respectively) and Def-EX (47.3 ± 11.8 g, p = 0.018, 35.4 ± 10.1 g, p = 0.036 respectively). Area under the curve (AUC) for hunger, desire to eat and prospective food consumption were significantly higher in Def-EI compared with both CON (p = 0.0001) and Def-EX (p = 0.0001). AUC for fullness was significantly lower on Def-EI compared with CON and Def-EX (p = 0.0001). Implicit wanting for sweet food was significantly lower on Def-EX (p = 0.031), relative to CON. CONCLUSION: Appetitive compensatory responses that are observed after iso-caloric energy restriction in adolescents with obesity are absent with acute exercise, which could contribute to optimize our impact on short-term energy balance.

The Effects of Using a Cycling Desk at School on Executive Function, Physical Fitness, and Body Composition in Primary School Children: Impact of Socioeconomic Status.

CONTEXT: Physical inactivity and sedentary behaviors are associated with adverse health outcomes in both adults and children. The purpose of this study was to investigate the effects of a 9-week program using a Cycle Desk during school time in French primary school children from high or low socioeconomic status (SES) on body composition, physical fitness (PF), and executive function. METHODS: Seventy-five (n = 75) children completed a test battery before and after 9 weeks of use of Cycle Desk to evaluate anthropometric characteristics, body composition, PF, and executive function. RESULTS: Body mass index increased significantly (P = .0095), while body fat decreased after the use of Cycle Desks (P < .0001). Specifically, lean mass increased in the high-SES group while it decreased in the low-SES group (P < .0001). After 9 weeks, there was an improvement in motor skills (P < .0001), upper and lower limbs' strength (P < .0001), and executive function performance (P < .0001). More specifically, the low-SES group had a greater improvement in motor skills and maximal aerobic speed between T0 and T1, compared to the high-SES group (P = .001, P = .023, respectively). In contrast, the high-SES group had a greater improvement in executive function at 9 weeks of use of Cycle Desk compared with the low-SES group (P = .0084). CONCLUSIONS: The promotion of low-intensity physical activity with the use of a Cycle Desk at school may help offset some adverse effects of excess sedentary behavior among children. Moreover, this strategy appears to be particularly effective in children from low-SES backgrounds. What's New: The use of a Cycle Desk during school time has no deleterious effects on PF as well as cognitive executive functions in primary children. Modifications are more beneficial in children from low SES.

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.

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.

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.

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.

Attrition rate and predictors of a monitoring mHealth application in adolescents with obesity.

BACKGROUND: Integrating mobile health (mHealth) into paediatric obesity treatment can provide opportunities for more personalized and lifetime treatment. However, high attrition rates pose a significant challenge. The current study attempts to better understand attrition by exploring (1) attrition rates of a monitoring mHealth application for usage over 14 days and (2) testing predictors of attrition in adolescents with obesity. METHODS: Participants were 69 adolescents between 12 and 16 years old who engaged in a multidisciplinary obesity treatment centre (either outpatient or inpatient) in two countries (Belgium and France). To assess the attrition rates, frequency distributions were used. To test the predictors of attrition, zero-inflated negative binomial regression was performed. RESULTS: Attrition rates were high, in the outpatient group, more than half of the participants (53.3%) used the app for only 0-7 days. In the inpatient group, this percentage was 24.1%. Only deficits in initiating (a component of executive functions) were a negative predictor of attrition, indicating that deficits in initiating lead to lower attrition rates. CONCLUSIONS: This study provides evidence for high attrition rates in mHealth interventions for adolescents with obesity and was the first to investigate psychological predictors of attrition to an mHealth monitoring tool in adolescents with obesity in treatment. Findings regarding predictors of attrition should be approached with caution due to the small sample size.

2022 French Report Card on Physical Activity and Sedentary Behaviors in Children and Youth: From Continuous Alarming Conclusions to Encouraging Initiatives.

BACKGROUND: Scientific evidence and public health reports keep highlighting the continuous and alarming worldwide progression of physical inactivity and sedentary behaviors in children and adolescents. The present paper summarizes findings from the 2022 French Report Card (RC) on physical activity for children and youth and compares them to the 2016, 2018, and 2020 RCs. METHODS: The 2022 edition of the French RC follows the standardized methodology established by the Active Healthy Kids Global Matrix. Ten physical activity indicators have been evaluated and graded based on the best available evidence coming from national surveys, peer-reviewed literature, government and nongovernment reports, and online information. The evaluation was also performed in children and adolescents with disabilities. Indicators were graded from A (high level of evidence) to F (very low level of evidence) or INC for incomplete. RESULTS: The evaluated indicators received the following grades: overall physical activity: D-; organized sport participation and physical activity: C; active play: F; active transportation: C; sedentary behaviors: D-; family and peers: D; physical fitness: C; school: C-; community and the built environment: F; government: B. CONCLUSIONS: While this 2022 French RC shows progression for 7 out of the 10 indicators considered, it also underlines the continuous need for actions at the local, regional, and national levels to develop better surveillance systems and favor a long-term improvement of youth movement behaviors.

Changes in Sedentary Time and Implicit Preference for Sedentary Behaviors in Response to a One-Month Educational Intervention in Primary School Children: Results from the Globe Trotter Pilot Cluster-Randomized Study.

School-based multi-component educational interventions have been encouraged to improve children's movement behaviors. The present study evaluates the effect of the Globe Trotter Initiative on physical activity (PA) level, sedentary time, physical fitness and activity preferences in primary school children. A total of 361 children (9−10 years) participated in this cluster-randomized trial. Nine schools were randomized as control (CON, 121 children) or Globe Trotter schools (GT, 240 children). Physical fitness, body composition, anthropometric characteristics, PA level, sedentary behaviors, physical self-perception, and activity preferences were evaluated at baseline (T0) and after the one-month intervention (T1). Grip strength performance and overall completion time of the obstacle course show a significant time effect (p < 0.001) in both groups (no group effect). PA level and physical self-perception did not significantly show time nor group effects. The sedentary behavior score displays a significant "time × group" interaction effect (p = 0.04) with a significant reduction between T0 and T1 in the GT group only (p < 0.001). The explicit liking for sedentary activities shows a significant "time × group" interaction (p = 0.02) with a significant decrease between T0 and T1 in the GT group only (p < 0.001). The explicit wanting for sedentary activities show a significant "time × group" interaction (p = 0.02) with a significant decrease between T0 and T1 in the GT group only (p < 0.001). The short-term, multi-component, behavioral, educational GT intervention had beneficial effects on primary-school-aged children's sedentary time and implicit preference for physical over sedentary activities.

Aqua Walking as an Appropriate and Healthy Winter and Summer Physical Practice? An Exploratory Study.

(1) Background: Aqua-walking in a natural environment is a health promoting physical activity that is gaining popularity and appropriate for a variety of populations, however, to date, there is little scientific evidence supporting the efficacy and safety of this activity for older adults. The objective was to propose a preliminary exploration of psychometric and metabolic responses to an acute Aqua walking session either during winter or summer in older adults Aqua walking exercisers. (2) Methods: Heart rate, body temperature, glycemia, and blood pressure were monitored in 37 (30 women, 7 men) participants aged 52 to 83 years old in two Aqua walking sessions (water at 13 °C and 18.5 °C, respectively). Anthropometry (body weight, waist, and hip circumferences), body composition, physical activity level, sedentary time, sleep quality, quality of life, physical self-perception, and perceived health and feelings on various parameters were also assessed. (3) Results: Present results revealed a greater quality of life, physical self-perception, and perceived health in aging Aqua walking exercisers compared to those found in the literature in younger populations. None of the metabolic or psychometric measurements were found to be different between classically calibrated Aqua walking sessions performed in winter compared to summer. By contrast, there was a time effect during the sessions for body temperature (p < 0.001), SBP (p = 0.17), perceived mental and physical well-being (p = 0.006 and p < 0.001, respectively), and anxiety (p < 0.001). Leg discomfort also showed a time effect (p = 0.0009) and interaction effect (p = 0.025). (4) Conclusion: Aqua walking appears here to be an accessible practice that can be performed all year long with a range of physical and mental benefits for older adults. Future studies should investigate the metabolic responses of Aqua walking in different populations.

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.

Effect of acute dietary- versus combined dietary and exercise-induced energy deficits on subsequent energy intake, appetite and food reward in adolescents with obesity.

BACKGROUND: Acute dietary-induced energy deficits have been shown to favor compensatory appetitive responses. The aim of this study was to compare energy intake (EI), appetite sensations and the hedonic responses to equivalent energy deficits induced by dietary restriction alone and combined with exercise in adolescents with obesity. METHODS: In a within-subjects design, seventeen adolescents with obesity (12-16 years, Tanner stage 3-5, 6 males) randomly completed three 14 h conditions: (i) control (CON); (ii) deficit induced by diet only (Def-EI) and; (iii) deficit induced by combined diet and physical exercise (Def-mixed). Breakfast and lunch were calibrated to generate a 500 kcal deficit in Def-EI and 250 kcal deficit in Def-mixed. A 250 kcal deficit was created through a cycling exercise set at 65% VO2peak in Def-mixed. Ad libitum EI, macronutrients and relative EI (REI) were assessed at dinner, subjective appetite sensations taken at regular intervals, and food reward measured before dinner. RESULTS: EI at dinner was significantly lower in Def-EI compared to CON (p = 0.014; Effect size (ES): -0.59 [-1.07; -0.12]), with no difference between Def-mixed and both CON and Def-EI. Total REI was lower in both deficit conditions compared with CON (Def-mixed: p < 0.001; ES: -3.80 [-4.27; -3.32], Def-EI: p < 0.001; ES: -4.90 [-5.37; -4.42] respectively), indicating incomplete compensation for the energy deficits. Absolute protein ingestion at dinner was lower in Def-EI than Def-mixed (p = 0.037; ES: -0.50 [-0.98; -0.03]) and absolute lipid ingestion was lower in Def-EI than in CON (p = 0.033; ES: -0.51 [-0.99; -0.04]). A higher proportion of protein and a lower proportion of carbohydrates was observed in Def-mixed than in Def-EI (p = 0.078; ES: -0.42 [-0.90; 0.04] and p = 0.067; ES: 0.44 [-0.03; 0.92] respectively). Total area under the curve for appetite sensations were similar between conditions. Explicit liking for sweet relative to savoury food was lower in Def-mixed compared to CON (p = 0.027; ES: -0.53 [-1.01; -0.06]) with no difference in food reward between Def-EI and CON. CONCLUSION: Neither of the two acute isoenergetic deficits led to subsequent appetitive compensation, with the dietary deficit even inducing a lower ad libitum EI at the subsequent dinner. Further studies are needed to better understand the appetitive response to dietary and exercise energy balance manipulations in this population.

Bone Response to High-Intensity Interval Training versus Moderate-Intensity Continuous Training in Adolescents with Obesity.

INTRODUCTION: Since adolescents with obesity are prone to bone fragility during weight loss, the aim was to compare the impact of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on bone density, geometry, and strength. METHODS: Sixty-one adolescents were randomly assigned to 2 cycling trainings (HIIT and MICT) and a control (CTR, without training) group. Anthropometry, dual-energy X-ray absorptiometry with hip structural analysis and the trabecular bone score (TBS) were assessed before and after the 16-week intervention. RESULTS: Body mass index (BMI) and fat mass (FM) percentage decreased at T1 versus T0 in both training groups (p < 0.001 for HIIT, p = 0.01 for MICT), though to a larger extent in HIIT (p < 0.05). Total body bone mineral density (BMD) and bone mineral content (BMC) increased in both training groups (p < 0.001), but to a greater extent in HIIT for BMC (p < 0.05). Lumbar spine BMD and BMC increased in both training groups (p < 0.001 for HIIT, p < 0.01 for MICT), with a time × group interaction between HIIT and CTR (p < 0.05) only. TBS increased in both training groups (p < 0.01 for HIIT, p < 0.05 for MICT). Hip BMD and BMC increased in both HIIT (p < 0.001 and p < 0.01) and MICT (p < 0.01 and p < 0.05). At the narrow neck (NN), endocortical diameter, width (p < 0.01), cross-sectional moment of inertia, and section modulus (Z) (p < 0.05) increased only in the HIIT group, such as BMD and Z (p < 0.05) at the intertrochanteric region (IT) and average cortical thickness (p < 0.001) and width (p < 0.05) at the femoral shaft. At the NN and IT, the buckling ratio decreased only in the HIIT group (p < 0.05), predicting higher resistance to fracture. CONCLUSIONS: In addition to inducing greater BMI and FM percentage decreases in comparison to MICT, HIIT improves multisite bone density, geometry, and strength, which heighten the justification for HIIT as part of weight loss interventions in adolescents with obesity.

Does the severity of obesity influence bone density, geometry and strength in adolescents?

BACKGROUND: Relationships between the severity of obesity and bone health remain underexplored. OBJECTIVES: To compare whole-body and localized bone mineral content (BMC) and density (BMD), trabecular bone score (TBS) and hip geometry and strength between adolescents with obesity versus extreme obesity. METHODS: This cross-sectional study included 154 adolescents (12-15 years, 62% females) who were classified as having obesity (OG, [95th-99th] percentile) or extreme obesity (EOG, >99th percentile). Fat mass (FM), lean mass (LM), BMC, BMD for total-body-less-head (TBLH), lumbar spine (LS), hip, TBS and geometric and strength indices at the narrow-neck (NN), femoral shaft (FS) and intertrochanteric regions (IT) were assessed by Dual-X-ray Absorptiometry (DXA). RESULTS: There was no significant sex-interaction. For both sexes, TBLH BMC and BMD were not different between groups. TBS was lower in EOG compared with OG in both sexes in univariate analysis and after adjustment with maturation and body weight (p < 0.05). Hip BMD was significantly higher in the EOG compared to OG only after adjustment with maturation and fat mass percentage (p < 0.05 for men, p < 0.01 for women). For both sexes, TBLH, LS and hip BMC and BMD positively correlated with weight, BMI, LM and FM. TBS negatively correlated with BMI-percentile in both sexes, with a negative correlation with FM for males alone. Hip BMC and BMD, BMD, ACT and CSA at the three hip sites positively correlated with BMI-percentile in males. CONCLUSIONS: Extreme obesity impacts bone health depending on anatomical sites, altering lumbar trabecular bone in both males and females adolescents.