Childhood overweight/obesity (OV/OB) is a major public health problem in Western countries, often accompanied with comorbidities (e.g., hypertension and insulin resistance) (i.e., metabolically unhealthy obesity—MUO). Among diet-related risk factors of OV/OB risk and MUO, meal patterns remain limitedly studied. The aim of this systematic review was to explore associations between meal patterns and the risk of childhood OV/OB and MUO in children/adolescents aged 2–19 years. Longitudinal studies and randomised controlled trials from PUBMED and Scopus published between January 2013 and April 2024 were retrieved. Twenty-eight studies were included, all of which reported on OV/OB risk, with none on MUO risk. Regular consumption of breakfast (n = 3) and family meals (n = 4) and avoiding dining while watching TV (n = 4) may be protective factors against childhood OV/OB, whereas meal skipping (primarily breakfast; n = 4) may be a detrimental factor. Mixed effects of meal frequency on OV/OB risk were observed; no effects of frequency of lunch or of fast-food consumption and of meals served at school were found. There was insufficient evidence to support the role of other patterns (meal timing, eating in other social contexts). Meals were mainly participant-identified, leading to increased heterogeneity. Research focusing on childhood MUO and the use of harmonised definitions regarding the assessment of meal patterns are highly warranted.

Childhood overweight/obesity (OV/OB) is a major public health problem, of greater concern when accompanied with comorbidities such as hypertension and insulin resistance leading to metabolically unhealthy obesity (MUO). Aetiologic associations between meal patterns, OV/OB risk and MUO are limited. The aim of this systematic review was to explore associations between meal patterns and the risk of childhood OV/OB and MUO. Longitudinal studies and randomised controlled trials from PUBMED and Scopus published between January 2013 - April 2024 were retrieved. Twenty-eight studies were included, all of which reported on OV/OB risk; none on MUO risk. Regular consumption of breakfast and family meals and avoiding dining while watching TV may be protective factors against childhood OV/OB, whereas meal skipping (primarily breakfast) may be a detrimental factor. Mixed effects of meal frequency on OV/OB risk were observed; no effects of frequency of lunch or of fast-food consumption and of meals served at school were found. There was insufficient evidence to support the role of other patterns (meal timing, eating in other social contexts). Meals were mainly participant-identified, leading to increased heterogeneity. Research focusing on childhood MUO and improved methodological approach (e.g. harmonised definitions) regarding the assessment of meal patterns are highly warranted.

Background: Childhood obesity is a growing global health concern. Metabolomics, the comprehensive study of metabolites within biological systems, offers a powerful approach to better define the phenotype and understand the complex biochemical alterations associated with obesity. The aim of this systematic review was to summarize current knowledge in the field of metabolomics in childhood obesity and to identify metabolic signatures or biomarkers associated with overweight/obesity (Ov/Ob) and Metabolically Unhealthy Obesity (MUO) in children and adolescents. Methods: We performed a systematic search of Medline and Scopus databases according to PRISMA guidelines. We included only longitudinal prospective studies or randomized controlled trials with ≥12 months of follow-up, as well as meta-analyses of the above that assessed the relation between metabolic signatures related to obesity and Body Mass Index (BMI) or other measures of adiposity in children and adolescents aged 2–19 years with overweight or obesity. Initially, 595 records were identified from PubMed and 1565 from Scopus. After removing duplicates and screening for relevance, 157 reports were assessed for eligibility. From the additional search, 75 new records were retrieved, of which none were eligible for our study. Finally, 7 reports were included in the present systematic review (4 reporting on Ov/Ob and 4 on MUO). Results: The presented studies suggest that the metabolism of amino acids and lipids is primarily affected by childhood obesity. Metabolites like glycoprotein acetyls, the Apolipoprotein B/Apolipoprotein A-1 ratio, and lactate have emerged as potential biomarkers for insulin resistance and metabolic syndrome, highlighting their potential value in clinical applications. Conclusions: There is a need for future longitudinal studies to assess metabolic changes over time, interventional studies to evaluate the efficacy of therapeutic strategies, and large-scale population studies to explore metabolic diversity across different demographics. Our findings reveal specific biomarkers in the amino acid and lipid pathway that may serve as early indicators of childhood obesity and its associated cardiometabolic complications.

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.