Pedicatric Obesity - Weight - Energy - Loss - Load

Although multidisciplinary treatment of pediatric obesity has shown its effectiveness in leading to weight loss and improvement in the physical, mental and social health of children and adolescents; maintaining these benefits remains a real challenge. Indeed, the literature clearly shows a short- to medium-term increase in weight, the mechanisms of which have yet to be identified in order to prevent it. Although cognitive, behavioral and nutritional adaptations have been highlighted to explain this weight regain, metabolic and energetic adaptations also seem to contribute. Indeed, a reduction in resting and total energy expenditure has been shown (in connection with changes in body composition and in particular lean mass), but also of the energy cost during locomotion and mobility, thus altering the daily energy balance. These energy adaptations are also accompanied by a modification in the use of energy substrates due to a modification of muscular metabolic flexibility in particular, leading to a reduction in lipid oxidation in favor of carbohydrates. Importantly, if this reduction in the use of lipids generates a counterproductive sparing of adipose tissue, thus slowing down weight loss, the increase in carbohydrate oxidation leads to an intensification of orexigenic signals at the central level, promoting nutritional compensations and positive energy balance and therefore contributing to weight regain. Thus, these adaptations of energy metabolism and their interactions with dietary control seem to be at the heart of the mechanisms limiting the success of obesity treatment, favoring weight gain. If these observations were made at the end of treatment programs lasting several weeks to months, a recent clinical work highlights the need to consider the kinetics and temporality of weight loss (weight loss variability and rate of weight loss), so as to identify the crucial stages where these adaptations take place and thus prevent their energy consequences. Thus, the