The effects of a mid-morning snack and moderate-intensity exercise on acute appetite and energy intake in 12-14-year-old adolescents

Impact of physical activity on caloric and macronutrient intake in children and adolescents: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Physical activity is widely promoted to maintain and improve health across all ages. Investigating how physical activity affects subsequent food intake provides insight into the factors that contribute to maintaining energy balance and effective weight management.

OBJECTIVE

This systematic review and meta-analysis summarizes the evidence on the effect of acute physical activity on subsequent food intake in children and adolescents.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA) were applied. Randomized controlled trials (RCTs) objectively measuring post-exercise energy intake in children and adolescents aged 5 to 18 years were included. Studies with self-reported food intake were excluded. The databases PubMed, Web of Science and Cochrane Library were searched for RCTs, and the data were summarized at a qualitative and quantitative level. Version 2 of the Cochrane risk-of-bias tool for randomized trials was used to assess risk of bias. Changes in energy intake were examined with random effects meta-analysis. (PROSPERO: CRD42022324259).

RESULTS

Out of 9582 studies, 22 RCTs with cross-over design remained eligible for meta-analysis. The primary outcome was post-intervention energy intake up to the next 24 h. Heterogeneity of studies was moderate, with an I2 of 57%. The median (interquartile range, IQR) energy expended while exercising was 240 (158) kcal. Meta-analysis of 41 study arms (exercise n = 780 and control n = 478) showed no differences in total energy intake between the exercise and control group with a mean difference MD = 23.31 [-27.54, 74.15] kcal. No subgroup differences were found. Macronutrient intake and appetite sensations where not substantially affected.

CONCLUSION

Engaging in exercise is a suitable means of raising activity-induced energy expenditure, without causing any noticeable changes in food intake or hunger within a single day.

Post-moderate-intensity exercise energy replacement does not reduce subsequent appetite and energy intake in adolescents with obesity

Exercise modifies energy intake (EI) in adolescents with obesity, but whether this is mediated by the exercise-induced energy deficit remains unknown. The present study examined the effect of exercise with and without dietary replacement of the exercise energy expenditure on appetite, EI and food reward in adolescents with obesity. Fourteen 12–15-year-old adolescents with obesity (eight girls; Tanner 3–4; BMI 34·8 (sd 5·7) kg/m2; BMI z score 2·3 (sd 0·4)) randomly completed three experimental conditions: (i) rest control (CON); (ii) 30-min cycling (EX) and (iii) 30-min cycling with dietary energy replacement (EX + R). Ad libitum EI was assessed at lunch and dinner, and food reward (Leeds Food Preference Questionnaire) before and after lunch. Appetite was assessed at regular intervals. Lunch, evening and total EI (excluding the post-exercise snack in EX − R) were similar across conditions. Lunch and total EI including the post-exercise snack in EX + R were higher in EX − R than CON and EX; EX and CON were similar. Total relative EI was lower in EX (6284 (sd 2042) kJ) compared with CON (7167 (sd 2218) kJ; P < 0·05) and higher in EX + R (7736 (sd 2033) kJ) compared with CON (P < 0·001). Appetite and satiety quotients did not differ across conditions (P ≥ 0·10). Pre-meal explicit liking for fat was lower in EX compared with CON and EX + R (P = 0·05). There was time by condition interaction between EX and CON for explicit wanting and liking for fat (P = 0·01). Despite similar appetite and EI, adolescents with obesity do not adapt their post-exercise food intake to account for immediate dietary replacement of the exercise-induced energy deficit, favouring a short-term positive energy balance.

Within-person compensation for snack energy by US adults, NHANES 2007-2014

BACKGROUND

Most Americans snack and some snack several times a day; however, compensatory dietary and eating behaviors associated with snacking in free-living individuals are poorly understood.

OBJECTIVE

The aim of the study was to examine within-person differences in reported energy intake and eating patterns on a snack day relative to a no-snack day.

METHODS

We used 2 d of dietary recall data from the NHANES 2007-2014 to replicate the crossover nutrition study paradigm in a natural setting. Respondents reporting a snack episode in only one of two available dietary recalls were eligible for inclusion in the study (n = 1,917 men and 1,860 women). We used multivariable regression methods to compare within-person differences in quantitative, qualitative, and eating pattern outcomes between the snack and no-snack recall days.

RESULTS

On the snack day, snack episodes provided (mean difference and 95% CI) 493 (454, 532) kcal of energy in men and 360 (328, 392) kcal in women. The 24-h energy intake on snack day was higher by 239 (140, 337) kcal in men and 219 (164, 273) kcal in women (P < 0.0001). On the snack day, both men and women were more likely to skip main meals and reported lower energy intake from main meals (P < 0.0001); however, the energy density of foods or beverages reported on the snack compared with no-snack days were not different. Fruit servings were higher on the snack day (P ≤ 0.0004), but intakes of vegetables and key micronutrients did not differ. The 24-h ingestive period was longer on the snack day (P < 0.0001).

CONCLUSIONS

Free-living men and women partially compensated for snack energy by decreasing energy intake from main meals without adverse associations with qualitative dietary characteristics or time of meal consumption. Women compensated to a smaller extent than men. Thus, over the long term, snack episodes may contribute to positive energy balance, and the risk may be higher in women.