How much protein do I need to lose fat?

Most people losing fat do well on 1.2 to 1.6 grams of protein per kilogram of body weight a day, the range in the US Dietary Guidelines. At 180 pounds that’s about 100 to 130 grams, or 35 to 45 grams at each of three meals. Under that is too low, and many people are. Lean people who lift hard need more. The Gyroscope app personalizes yours; these ranges show you if you’re too low.

Why protein matters more on a diet

When you eat less, your body takes some of the missing energy from muscle. Protein and lifting push it to take more from fat. Eating less is like a company cutting costs: protein and lifting tell it to cut the waste and keep the staff.

In a 2016 trial, 40 young men ate 40% fewer calories for four weeks and trained six days a week. On 2.4 g of protein per kg of bodyweight, they gained 2.6 pounds (1.2 kg) of lean mass and lost 10.6 pounds (4.8 kg) of fat. On 1.2 g they gained almost no lean mass and lost 7.7 pounds (3.5 kg) of fat.

The ranges

If you have more than a fifth of your weight to lose, count from a weight nearer your goal: your goal plus a fifth of what you weigh now. That’s why the last row isn’t counted from 240. The protein calculator does this for you.

Lean people who lift hard on a diet need more: 2.3 to 3.1 g per kg of lean mass, the part of you that isn’t fat, in a 2014 review. For a 180 pound man at 15% bodyfat, that’s about 160 to 215 grams.

Where the numbers come from

The 2025 to 2030 US Dietary Guidelines set 1.2 to 1.6 g per kg of body weight a day. The old figure you still see, 0.8 g per kg, is the minimum that covers basic needs, never a target for dieting. A 2018 review of 49 trials with 1,863 people found that the muscle people gained from lifting stopped growing with more protein past about 1.6 g per kg of bodyweight. For people losing weight on GLP-1 drugs, a 2025 advisory from four US nutrition and obesity societies suggests about 1.5 g per kg of lean mass.

Many people eat too little, more so with age. In a US national survey of 11,680 adults over 50, up to 46% of the oldest ate less than even the old minimum.

What to do

• Find your range with the protein calculator, then aim for the middle of it.
• Put protein first at every meal: eggs, Greek yogurt, fish, chicken, beans, tofu.
• Lift two or three days a week. Protein keeps more muscle when the muscle is being used.
• If you have kidney disease, your doctor sets the number.