Consuming less energy than the body uses, so that stored fat (and, if the deficit is too large, muscle) is used to make up the difference. The basis of every fat-loss diet.
The size of the deficit determines what is lost. Controlled studies in athletes show that a deficit producing about 0.5 to 1 percent of body weight lost per week preserves muscle and strength, while faster loss costs both. High protein intake and continued heavy resistance training further protect muscle in a deficit.
This article is for information and education only. It is not medical advice and does not replace a consultation with a physician. Anabolic-androgenic steroids are prescription medicines in most countries and are controlled substances in many. Check the law where you live.