Lose Fat, Keep Muscle: The Order Matters

Most people who set out to lose weight lose some of both fat and muscle. Often the scale drops, and months later it is back with less muscle than before and the same fat or more. The reason is the order of operations. Cutting food first and adding training later, if at all, tells the body to shed whatever is expensive to maintain, and muscle is expensive.

Why the body gives up muscle

In a calorie deficit, the body has to make up the missing energy from its own stores. The body does not know the goal is to look better. It reads the shortfall as a reason to cut costs, and muscle burns calories around the clock just to exist. Without a signal that the muscle is needed, some of it goes. Studies of dieting without resistance training commonly find that a quarter or more of the weight lost is lean tissue.

Two signals keep the muscle. The first is loading it. Resistance training tells the body that this tissue is in use and must be kept. The second is protein. Amino acids arriving several times a day give the muscle the raw material to repair itself, and a high protein intake during a deficit shifts the loss toward fat.

The order

1. Resistance training first. Two to four sessions a week, covering the whole body, with weights heavy enough that the last few reps are hard. Start this before the diet changes, or at the very least the same week.

2. Protein second. We set the target at 1 gram per pound of lean body mass per day, split into 3 to 4 meals of 30 to 50 grams. A woman with 105 pounds of lean mass eats about 105 grams a day.

3. The deficit third, and moderate. Roughly 300 to 500 calories a day below maintenance, which works out to about half a pound to a pound of fat per week. Larger deficits lose weight faster and lose more of it from muscle.

How we know it is working

The scale cannot tell fat from muscle. A body composition scan can. An InBody scan takes about a minute and separates lean mass from fat mass. A DEXA does the same with more precision and shows where the fat sits. We scan at the start, then every month or two. If fat mass is falling and lean mass is holding or rising, the plan is working even if the scale is moving slowly. If lean mass is dropping, the deficit is too large or the training and protein are not landing, and we adjust.

A 48 year old man who loses 20 pounds this way looks very different from one who loses 20 pounds on diet alone, even at the same final weight. The first has most likely kept his muscle. The second has likely lost a good share of it, and muscle is slow to rebuild.

That's why we measure it, not just weigh it.

This article is educational and is not medical advice.

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