The Claim
In men with overweight or obesity, a 5-week isocaloric diet with reduced protein (0.9 g/kg/day) and increased carbohydrates results in a significant reduction in fat mass by approximately 1.1 kg and a non-significant trend toward reduction in lean body 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 men with overweight or obesity, eating a 5-week diet with less protein and more carbohydrates, while keeping total calories the same, leads to a loss of about 1.1 kg of fat mass, with little to no change in muscle mass.
See the scientific wording
In men with overweight or obesity, a 5-week isocaloric diet with reduced protein (0.9 g/kg/day) and increased carbohydrates leads to a significant reduction in fat mass by approximately 1.1 kg, while lean body mass shows only a non-significant trend toward reduction.
When protein intake drops, the liver releases a hormone called FGF21, which signals fat tissue to burn more energy as heat. This increases the body's total energy use, so stored fat gets broken down and used for fuel, even when total calories stay the same. Muscle tissue is preserved because the body prioritizes using fat for energy under these conditions.
What the research says
1 studyIn a study, men who ate less protein and more carbs — but the same total calories — lost about 1.1 kg of fat over five weeks, and their muscle barely changed. So yes, this diet helped them lose fat without losing much muscle.
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.