If you're someone who lifts weights regularly, whether you're eating more or fewer calories than your body needs is one of the biggest factors in how fast you gain muscle or lose fat.
Evidence from Studies
Supporting (1)
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The study found that whether people ate fewer calories every day or just on two days a week, they gained similar muscle and lost similar fat when lifting weights, as long as total calorie reduction was the same. This supports the idea that how big the calorie deficit is matters most for body changes.
Contradicting (1)
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Effect of Small and Large Energy Surpluses on Strength, Muscle, and Skinfold Thickness in Resistance-Trained Individuals: A Parallel Groups Design
The study found that eating much more than you burn leads to more fat gain, but doesn't help build much more muscle, even if you're lifting weights. So, how big your calorie surplus is doesn't seem to be the main thing driving muscle growth.
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.