The Study
Combined diet and physical activity effects on health-related outcomes in people with overweight or obesity: an overview of systematic reviews
This study looked at lots of other studies that tested whether eating better and moving more helps people lose weight and get healthier. It found that, on average, doing both together works better than just one. But it didn’t do new experiments—it just added up what other studies found, so we can’t be 100% sure it’s always true.
Analysis score
Maximum 100 for a systematic review with meta-analysis.
Where the score came from
When people who are overweight eat better and exercise together, they lose more fat, keep more muscle, and feel healthier than if they only diet or only exercise.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 547 / 100
Quality score
The highest quality evidence. Systematic reviews and meta-analyses that pool randomized controlled trials, giving the most reliable summary of experimental evidence.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Even small weight losses (like 2–3 kg) combined with better fitness and muscle retention can significantly lower disease risk and improve daily function, especially when programs last 6–12 months with support.
- 2Combined diet and exercise led to 1.7–6.3 kg more weight loss than diet alone; cut type 2 diabetes risk by half; improved blood sugar and cholesterol even without extra weight loss; preserved muscle and bone in older adults.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Frontiers in Nutrition
Year
2026
Authors
Atef Salem, Achraf Ammar, Khaled Trabelsi, O. Boukhris, J. Heydenreich, H. Ghazzawi, A. Amawi, G. Grosso, Piotr Żmijewski, H. Jahrami, Waqar Husain, Hamdi Chtourou, W. Schöllhorn
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Claims (7)
People who start exercising after losing weight are less likely to regain the weight, even if they do not continue to lose fat.
People with moderate body fat can lose fat while keeping their muscle mass unchanged.
In older adults with obesity, combining diet changes with resistance exercise reduces body fat and maintains muscle, bone, strength, and physical function, while dieting alone causes significant loss of muscle and bone.
In adults with overweight or obesity, combining diet and supervised exercise for 6 to 12 months leads to greater weight loss and better body composition—more fat loss and less muscle loss—than dieting or exercising alone, resulting in improved metabolic health and physical function.
In adults with overweight or obesity, combining diet changes with physical activity results in small but consistent improvements in blood sugar, insulin resistance, triglycerides, and inflammation markers, even when little extra weight is lost compared to diet alone.
In children and adolescents with overweight or obesity, structured programs that involve families and combine diet and physical activity lead to the most consistent reductions in BMI and BMI-z scores at 6 months, but these reductions decrease within 6 to 12 months after the program ends if no ongoing support is provided.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.