The Study
The impact and utility of very low-calorie diets: the role of exercise and protein in preserving skeletal muscle mass
This study is like a teacher summarizing what different science classes have said about diets and muscles, but without checking if those classes did their experiments right. So we can say 'maybe' or 'it seems like' certain things help, but we can't say for sure they cause changes.
Analysis score
Maximum 5 for a narrative review.
Where the score came from
Eating very few calories helps you lose weight fast, but your body might also eat your muscles. You can stop that by lifting weights and eating enough protein.
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 52 / 100
Quality score
Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — if you're trying to lose weight and don't lift weights, you'll likely lose muscle, which weakens you and makes it harder to stay healthy long-term.
- 2Lifting weights 3 times a week while eating 800–1200 calories/day kept muscle mass in obese adults.
- 3Eating 1.2–1.6 grams of protein per kg of body weight helped too.
- 4Without weights, muscle dropped even with enough protein.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Current Opinion in Clinical Nutrition and Metabolic Care
Year
2023
Authors
Tom Anthonius Hubertus Janssen, Derrick W. Van Every, Stuart M Phillips
Related Content
Claims (7)
Trained individuals can lose body fat and gain muscle at the same time while consuming fewer calories than they burn.
In obese adults on a very low-calorie diet, doing resistance exercise three times per week stops skeletal muscle mass from decreasing, even if protein intake is sufficient but not increased, because it increases muscle protein synthesis and reduces the breakdown caused by low energy intake.
In older adults with obesity and metabolic syndrome, eating very few calories without lifting weights leads to muscle loss even when protein intake is sufficient, but adding weight training to adequate protein intake prevents muscle loss and improves metabolic health.
In obese adults on a very low-calorie diet, consuming 1.2 to 1.6 grams of protein per kilogram of body weight each day results in less muscle loss than consuming less protein, because muscle protein synthesis remains higher at this intake level.
Very low-calorie diets cause increased muscle loss and faster decline in physical function in older adults at risk of sarcopenia, even if they consume more protein.
Consuming very low-calorie diets (800–1200 kcal/day) leads to measurable loss of skeletal muscle mass in people with low body fat or those who do not perform resistance training, because muscle protein breakdown exceeds synthesis during extended energy restriction.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.