Mostly true: “You need more protein when you're losing weight.”

Mostly true

Evidence confidence Moderate

The short answer

Eating more protein while you cut calories helps you keep a little more muscle, so eating more protein than most people usually eat makes sense.

What this means for you

If you are cutting calories, eating more protein than most people usually eat is a sensible, modest help for holding on to muscle. If your usual intake already meets the target of about 0.55 to 0.7 gram per pound a day, you do not need more. It does not replace the calorie deficit, which is what drives fat loss, and strength training is the other main way to protect muscle (see our card on lifting weights while losing weight). People at a steady weight usually do not need extra protein, which is why this advice is specific to weight loss.

Your next step

If you are cutting calories, aim for about 0.55 to 0.7 gram of protein per pound of body weight a day (about 100 to 130 grams for a 180-pound adult), and lift weights two or three times a week; if you lift most days, up to about 1 gram per pound is reasonable.

Who should be careful?

Safety note: People with chronic kidney disease need a protein target set with their care team. Kidney nutrition guidelines give specific protein advice that depends on the stage of disease and whether a person is on dialysis.

Talk to a healthcare professional if: you have chronic kidney disease, or you are losing weight or muscle without trying.

Why this confidence?

Two reviews, one of 24 trials and one of 47 trials, found that eating more protein while cutting calories saves a little muscle, and the first also found a little more fat lost. Confidence is moderate because the trials were short and varied, the gains were small, and the extra muscle did not bring clear gains in strength or physical function.

The facts

Eating more protein while you cut calories helps you keep a little more muscle, so eating more protein than most people usually eat makes sense. In 24 trials lasting about 12 weeks on average, higher-protein diets saved about 1 pound more lean mass and took off about 2 pounds more fat than standard-protein diets. A publicly funded review of 47 weight-loss trials found the same muscle benefit, but no clear gain in strength or physical function.

The bigger picture

In the 24-trial analysis, higher-protein diets also took off about 1.7 pounds more weight, with blood pressure and cholesterol changing about the same as on standard-protein diets. The review behind the new US Dietary Guidelines looked at 30 trials, most in adults cutting calories: 16 of the 25 that measured body fat found more fat lost with higher protein, but only 8 of the 22 that measured lean mass found more muscle kept. So the muscle benefit is real on average but small, and it does not show up in every trial.

Dose Matters

The RDA, the amount set to cover most healthy adults, is about 0.36 gram of protein per pound of body weight a day, or about 65 grams for a 180-pound adult. The 2025 to 2030 US Dietary Guidelines advise about 0.55 to 0.7 gram per pound; for a 180-pound adult, that is about 100 to 130 grams a day. US adults eat about 0.45 gram per pound a day on average, below that range. That range comes mostly from weight-loss trials, and the two experts who wrote that review have received money from beef, pork and dairy groups. A publicly funded review of 47 weight-loss trials found a similar line: people who ate more than about 0.6 gram per pound kept more muscle, and people who ate less than about 0.45 gram per pound were more likely to lose it. There is no official upper limit, and in short trials, healthy adults on high-protein diets, often about 0.9 gram per pound a day, showed no consistent signs of kidney harm.

Does more protein help you feel fuller while dieting?

Yes, in most studies that checked. In the 24-trial review, 3 of the 5 trials that measured fullness found people felt fuller on the higher-protein diet.

Sources (6)

“You need more protein when you're losing weight.”

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