Interventions for the prevention of weight gain during festive and holiday periods in children and adults: A systematic review.

Some periods during the year, such as festive and summer holiday periods, have been associated with weight gain. We aimed to assess the effect of interventions for the prevention of body weight gain during festive and holiday periods in children and adults. A systematic search was conducted in six databases and supplementary sources until January 4, 2023. We included randomized controlled trials (RCTs), cluster-RCTs, and non-RCTs. Our primary outcome measure was the change in body weight in adults or the change in BMI z-score or BMI percentile in children and adolescents. From 4216 records, 12 primary studies (from 22 reports) met the inclusion criteria-10 from the United States, one from the United Kingdom, and one from Chile. Two studies had a low risk of bias, two moderate, seven high, and one critical risk of bias. The meta-analysis in children included four of seven studies during the summer holidays (six interventions) and showed a mean difference in BMI z-score favoring the intervention group (-0.06 [95% CI -0.10, -0.01], p = 0.01, I 2  = 0%, very low certainty evidence). The meta-analysis in adults included five studies during festive periods with a mean difference in weight favoring the intervention group (-0.99 kg [95% CI -2.15, 0.18], p = 0.10, I 2  = 89%, very low certainty evidence). This review has highlighted potential interventions to prevent the increase in body weight during holiday periods. More work is needed to improve the quality of the evidence and to extend it to countries outside of the United States and United Kingdom and to the adolescent population.