Losing Fat and Gaining Muscle at the Same Time

The usual advice says you cannot lose fat and build muscle at once. Losing fat needs a calorie deficit, building muscle needs extra material, so you pick one. For some people that is close to true. For many others, doing both at the same time, called body recomposition, is realistic.

How it works

Muscle is built when two things happen together: a training signal that tells the muscle to grow, and enough protein to supply the building blocks. Muscle growth does not require eating a large surplus of total calories, as long as protein is high and the body has energy available.

Fat stores are that energy. A person carrying extra body fat has a large reserve. With a modest deficit, the body can draw on fat for fuel while still directing protein toward muscle repair and growth. The deficit has to stay modest. A steep cut pushes the body to break down muscle along with fat.

Who can expect it

Recomposition is most likely in people who have the most room to change.

• People new to strength training. Untrained muscle responds quickly to a new signal.
• People returning after time off. Muscle that was built before tends to come back faster.
• People with higher body fat. A larger fat reserve supplies more energy during a deficit.
• Older adults starting to lift. Gains are slower, but they still happen with enough protein.

A lean person who has lifted seriously for years has much less room. For them, building muscle usually requires eating at or above maintenance, and losing fat is a separate phase.

What it takes

The plan is simple, not easy.

• Strength training two to four times a week, with the weight increasing over time.
• Protein at about 1 gram per pound of lean body mass per day, spread across 3 to 4 meals of 30 to 50 grams.
• A modest calorie deficit, or calories near maintenance.
• Sleep. In a small controlled study, people dieting on short sleep lost less fat and more lean mass than they did on full nights.

How you would know

Lose a pound of fat and gain a pound of muscle in a month, and the scale shows no change. It looks like nothing is working.

A body composition scan separates the two. An InBody splits weight into fat mass and lean mass, with lean mass by arm, leg and trunk. Over a few monthly scans under the same conditions, you can see fat mass trend down while lean mass holds or rises. The changes are small each month, often around a pound, so the trend across several scans matters more than any one reading.

If the scale has stalled but your lifts keep climbing, it is worth finding out what changed underneath. That is the kind of thing we measure. You can pick your time right after you buy.

Book an InBody scan at HYBRD Health ($39)

This article is educational and is not medical advice.