Summary: In a trial in overweight children, high-intensity interval training combined with a dietitian-designed diet improved body composition, cardiovascular and endothelial function, and lipids more than HIIT alone or moderate-intensity continuous training over 9 weeks.
PICO Summary
| Element | Detail |
|---|---|
| Population | 90 overweight children aged 9–12 (BMI ≥23), equal sex ratio, in three groups of 30; randomised controlled trial, China/Poland. |
| Intervention | High-intensity interval training (100–120% maximal aerobic speed) plus a registered-dietitian diet plan, for 9 weeks (Joint Intervention). |
| Comparison | Moderate-intensity continuous training (60–80% MAS), or HIIT alone without diet. |
| Outcome | All three groups reduced BMI and fat mass; both HIIT groups reduced body-fat percentage more than continuous training (p<0.05). The combined group had superior cardiac output, vasodilatory capacity, waist circumference, BMI, and lipids, with lower endothelin-1 and von Willebrand factor and higher flow-mediated dilation and nitric oxide than HIIT alone (p<0.05). |
HIIT plus diet in childhood obesity
RCT · overweight children · 9 weeks
Adding a dietitian-designed diet to HIIT more than doubled fat-mass loss versus HIIT alone and produced greater gains in vascular and endothelial function over 9 weeks.
Expert Commentary
This is a well-structured three-arm trial that answers two useful questions at once, whether higher-intensity exercise helps and whether adding diet helps further, and the results are coherent on both. The clearest message is additive: combining HIIT with a properly designed diet outperformed exercise alone across body composition, lipids, and vascular measures, which supports multicomponent rather than single-modality programmes for childhood obesity. The endothelial findings are the most interesting, since improvements in nitric oxide, flow-mediated dilation, endothelin-1, and von Willebrand factor suggest that the early vascular dysfunction of paediatric obesity is reversible with lifestyle change, and reassuringly HIIT was tolerated without adverse effects. I would keep the limits in view, a nine-week controlled-setting study with undetailed dietary specifics, no long-term maintenance data, and a population of overweight rather than severely obese children, so durability and real-world replication are unproven. Can I use this with my patients? Yes, as practical guidance. For overweight children I would recommend combining supervised, appropriately progressed higher-intensity activity with dietitian-guided dietary change, framed as a family lifestyle approach rather than a child’s diet, while emphasising that fitness and vascular gains arrive before, and independent of, large weight loss.
References
Wang X, Meng Q, Liu T, Lipowski M. Effects of high-intensity interval training combined with dietary intervention on body composition, cardiovascular function, endothelial cell function and blood lipid indexes in children with obesity: a randomized controlled trial. Front Public Health. 2025;13:1698573. doi:10.3389/fpubh.2025.1698573