The Study
Impact of Protein Intake during Weight Loss on Preservation of Fat-Free Mass, Resting Energy Expenditure, and Physical Function in Overweight Postmenopausal Women: A Randomized Controlled Trial
This study gave two groups of women different diets while they lost weight and then checked what happened to their muscles and energy levels. Because they randomly assigned who got which diet, we can guess that the diet might have caused the differences we saw — but only for handgrip strength. For everything else, both groups lost about the same, so we can't say the protein diet made a difference.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study tested if eating more protein (like extra shakes) helps older women keep their muscles and energy when dieting to lose weight.
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 570 / 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.
- 1Even with more protein, women still lost muscle and burned less energy at rest — but their hand strength stayed steady.
- 2This suggests protein alone isn't enough to protect most muscle during weight loss, but might help keep grip strength.
- 3Women lost about 5 kg either way.
- 4Both groups lost similar muscle and energy use.
- 5Only the normal-protein group lost handgrip strength (by 1.7 kg); the high-protein group didn't.
- 6Weight loss speed and calorie deficit mattered more than protein for muscle loss.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Obesity Facts
Year
2021
Authors
I. Englert, A. Bosy-Westphal, S. Bischoff, K. Kohlenberg-Müller
Related Content
Claims (6)
After losing weight, overweight postmenopausal women continue to burn fewer calories at rest, no matter how much protein they eat. Only those who consumed a normal amount of protein showed a partial increase in resting calorie burn during a six-month follow-up period.
Among overweight women after menopause who are losing weight on a reduced-calorie diet, consuming more protein (1.5 grams per kilogram of body weight per day) does not prevent loss of muscle mass or reduce the drop in resting calorie burn compared to consuming less protein (0.8 grams per kilogram per day).
Among overweight women after menopause who are losing weight, those eating more protein maintain handgrip strength better than those eating less protein, but there is no difference in balance, walking speed, or overall physical performance scores.
In overweight postmenopausal women losing weight, how quickly they lose weight and how large their calorie deficit is predict more of the loss of lean tissue than how much protein they consume, together explaining up to 39% of the variation in lean mass loss.
For overweight women after menopause who are losing weight, eating more protein does not improve their ability to walk, stand, or move quickly, even if it may increase hand strength.
People who consume about 1.3 grams of protein per kilogram of body weight and include dairy while eating fewer calories maintain their strength levels.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.