The effects of acute exercise on food intake and appetite in adolescents with and without obesity: A systematic review and meta-analysis

This systematic review and meta-analysis synthesized evidence pertaining to consummatory and appetitive responses to acute exercise in children and adolescents with and without obesity (5-18 years). Articles reporting on supervised, controlled trials of any modality, duration, or intensity with laboratory-measured food intake were found using MEDLINE, EMBASE, and Cochrane up to July 2023. Differences between conditions in laboratory energy and macronutrient intake, appetite sensations, and food reward were quantitatively synthesized using random-effects meta-analyses. Thirty-five studies were eligible for the systematic review of energy intake, consisting of 60 distinct intervention arms with lean (n = 374) and overweight/obesity participants (n = 325; k = 51 eligible for meta-analysis). Study quality as indicated by the Effective Public Healthy Practice Project tool was rated as low and moderate risk of bias for 80% and 20% of studies, respectively. Acute exercise had no significant effect on energy intake during an ad libitum test meal (mean difference [MD] = -4.52 [-30.58, 21.54] kcal, p = .729). Whilst absolute carbohydrate intake was lower after exercise (23 arms; MD = -6.08 [-11.26, -0.91] g, p = .023), the proportion of carbohydrate was not (30 arms; MD = -0.62 [-3.36, 2.12] %, p = .647). A small elevation in hunger (27 arms; MD = 4.56 [0.75, 8.37] mm, p = .021) and prospective food consumption (27 arms; PFC; MD = 5.71 [1.62, 9.80] mm, p = .008) was observed post-exercise, but not immediately prior to the test meal (Interval: Mdn = 30 min, Range = 0-180). Conversely, a modest decrease in explicit wanting for high-fat foods was evident after exercise (10 arms; MD = -2.22 [-3.96, -0.47] mm, p = .019). Exercise intensity (p = .033) and duration (p = .013) moderated food intake only in youth with overweight/obesity, indicating lower intake at high intensity and short duration. Overall, acute exercise does not lead to compensation of energy intake or a meaningful elevation of appetite or food reward and might have a modest benefit in youth with overweight/obesity if sufficiently intense. However, conclusions are limited by substantial methodological heterogeneity and the small number of trials employing high-intensity exercise, especially in youth with overweight/obesity.