The Study
Preservation of muscle mass assessed by ultrasound during a meal replacement-based hypocaloric intervention in obese individuals: a real-world clinical trial.
This study watched a group of people eat meal replacements for 12 weeks and noticed they lost weight and their muscles looked bigger. But it didn't compare them to people who ate normal food, so we don't know if the meal replacements caused the changes or if it just happened by chance.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study looked at older adults with obesity who ate one meal a day using a special shake instead of regular food, while eating less overall.
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 540 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — gaining muscle while losing fat is rare and valuable, especially for older adults who often lose muscle when dieting.
- 2After 12 weeks, they lost weight and fat, but their thigh muscle got bigger — from 1.7 cm to 2.3 cm thick.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutricion hospitalaria
Year
2026
Authors
D. D. de Luis, O. Izaola, David Primo, Daniel Rico Bigues, J. J. López Gómez
Related Content
Claims (6)
People can lose one pound of fat each week while keeping all their muscle mass unchanged.
Obese adults who followed a 12-week hypocaloric meal replacement program showed lower levels of fasting glucose, insulin, HOMA-IR, triglycerides, and LDL cholesterol compared to their baseline levels.
Obese adults who followed a 12-week hypocaloric meal replacement program experienced measurable decreases in body weight, body mass index, and waist circumference.
Obese adults who followed a 12-week hypocaloric meal replacement program lost weight primarily through a reduction in body fat.
In older obese adults, a 12-week low-calorie meal replacement diet led to measurable increases in thigh muscle size and thickness, even as overall body weight and fat decreased.
Obese adults who followed a 12-week hypocaloric meal replacement program had lower rates of metabolic syndrome, central obesity, high triglycerides, high blood pressure, and high blood sugar.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.