The Claim
In young women with normal BMI but high body fat percentage (≥33.3%), a 500 kcal daily caloric restriction for 4 weeks reduces body weight by approximately 2.5 kg and fat mass by 1.45–1.55 kg, and causes a significant loss of 1.21 kg of muscle mass.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
In young women with normal body weight but high body fat, eating 500 fewer calories per day for four weeks results in a 2.5 kg weight loss, a 1.45–1.55 kg reduction in fat mass, and a 1.21 kg loss of muscle mass.
See the scientific wording
In young women with normal BMI but high body fat percentage (≥33.3%), a 500 kcal daily caloric restriction for 4 weeks reduces body weight by approximately 2.5 kg and fat mass by 1.45–1.55 kg, but also causes a significant loss of 1.21 kg of muscle mass, indicating that caloric restriction alone may compromise lean tissue preservation.
When the body gets fewer calories than it needs, it shifts into survival mode and starts breaking down muscle tissue for energy, even if there is plenty of fat stored. This happens because the body reduces signals that build muscle and increases signals that break it down, and without exercise to counteract this, muscle mass decreases.
What the research says
1 studyWhen young women with normal weight but high body fat cut 500 calories a day for four weeks, they lost weight and fat—but also lost over a kilogram of muscle, even without exercising. The study proves this muscle loss happens just from eating less.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.