The Study
Effects of 1-Month Very-Low-Calorie Ketogenic Diet on 24-Hour Energy Metabolism and Body Composition in Women With Obesity
This study watched 17 women eat a super-low-calorie keto diet for a month and measured what happened to their bodies. It shows that their weight went down and their bodies started burning more fat — but it doesn't prove the diet caused those changes, because they weren't randomly assigned and there wasn't a fair comparison group.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
When you eat almost no carbs and very few calories, your body burns fat for fuel — but it also breaks down muscle to make sugar for your brain.
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 553 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Losing muscle while dieting makes it harder to keep weight off long-term because muscle burns more calories at rest.
- 2Weight dropped 7%: 62% from fat, 38% from muscle.
- 3Energy use fell 10%.
- 4Fat burning went up 11%, carbs down 65%.
- 5Muscle breakdown started on day one and kept going.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of Clinical Endocrinology and Metabolism
Year
2025
Authors
A. Basolo, P. Piaggi, Valentina Angeli, P. Fierabracci, Chiara Bologna, E. Vignali, Daniela Troiani, R. Jaccheri, C. Pelosini, Melania Paoli, G. Salvetti, Luca Chiovato, J. Krakoff, Alberto Landi, Ferruccio Santini
Related Content
Claims (8)
In women with obesity, following a very-low-calorie ketogenic diet for one month leads to higher breakdown of muscle protein and loss of lean tissue, driven by the body's requirement for glucose even when ketone bodies are available.
In women with obesity, following a very-low-calorie ketogenic diet for one month leads to a 10% drop in daily and nighttime calorie burning, which is mainly due to losing 5.6% of muscle and other lean tissue, not because the body's metabolism slows down on its own.
In women with obesity, following a very-low-calorie ketogenic diet for one month results in a 65% decrease in the body's use of carbohydrates for energy and an 11% increase in the use of fat for energy.
In 17 women with obesity, a one-month very-low-calorie ketogenic diet resulted in a 7% drop in total body weight, with 8.8% of that loss coming from fat mass and 5.6% from lean soft tissue.
Long-term adherence to very low-calorie, high-protein diets leads to diminished weight loss outcomes because of changes in metabolism and behavior.
In women with obesity, following a very-low-calorie ketogenic diet for one month leads to a continuous rise in protein breakdown starting within one day and continuing for the entire month, resulting in loss of lean body tissue.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.