The association between consumption of foods/food groups and the risk of overweight/obesity and metabolically unhealthy obesity in children and adolescents: a systematic review and meta-analysis

Existing studies have suggested an association between consumption of foods/food groups and the risk of childhood overweight/obesity (OV/OB) and metabolic unhealthy obesity (MUO). However, they are heterogeneous in terms of design, samples and outcomes, and most do not provide evidence of long-term longitudinal associations given their cross-sectional nature. The aim of the present work was to systematically review longitudinal evidence of the association between foods/food groups and the risk of OV/OB and MUO in children and adolescents aged 2–19 years. Two databases (Scopus and PubMed) were searched for original research conducted in Western countries. Prospective epidemiological studies (PES) and randomized controlled trials (RCTs) with exposures/interventions related to the consumption of foods/food groups, OV/OB- or MUO-related outcomes and ≥1-year follow-up were considered eligible. A narrative evidence synthesis, complemented by random-effects meta-analyses where feasible, was performed. The review protocol was registered in PROSPERO (ID: CRD42024496148). The narrative synthesis of 23 longitudinal studies revealed a detrimental effect of sugar-sweetened beverages (SSBs) (n = 8/10 PESs and 1/2 RCTs) and ultra-processed foods (UPFs) (n = 2/3 PESs), and a beneficial effect of full/higher-fat dairy products (n = 2/3 PESs) on OV/OB-related outcomes, although certainty in evidence was (very) low. Evidence was inconclusive for artificially sweetened beverages, fruits and vegetables (primarily 100% fruit juices), milk and total dairy products. Random-effects meta-analysis of PESs focusing on SSBs revealed a positive association with follow-up body mass index (n = 3, pooled beta: 0.16 kg/m2, 95%CI: 0.09, 0.23) but a non-significant association with change in BMI (n = 3, pooled beta: 0.07 kg/m2, 95%CI: −0.05, 0.19). Only 1 PES reported on MUO-related outcomes and revealed a potential beneficial link between higher-fat milk intake and selected cardiometabolic indices. In conclusion, consumption of SSBs is positively associated with indicators of childhood OV/OB risk. A detrimental effect of UPFs and a beneficial effect of higher-fat dairy products on childhood adiposity outcomes were also observed, but the available evidence remains limited and insufficient to draw robust conclusions. Data for other foods/food groups and OV/OB, as well as for their link with childhood MUO, remain scarce and inconclusive.