Why is my bodyfat not going down when I'm losing weight?

Usually because the percentage moves slowly and your scale’s estimate of it is noisy. Ten pounds of fat lost may move it only about 2 points, and a home scale’s error on a change can be 2 to 3 points. If your weight and your waist are both falling over a month, you’re losing fat.

Three reasons it stalls

1. The math is slow. Bodyfat is a share of your weight. Take a 200 pound person at 30%: 60 pounds of fat. Lose 10 pounds, all of it fat, and they’re at 50 out of 190, or 26%. Ten pounds of hard work moved the number 4 points. Lose 10 pounds with 3 of it lean mass and it’s 53 out of 190, or 28%.

2. The scale is noisy. In a 2023 lab test of 15 devices, the typical error on a change over 12 to 16 weeks was about 2 to 3 points. That’s about the size of the change you’re hoping to see.

3. Water moves. When you cut carbs or calories, you use up stored carbs, and each gram is stored with at least 3 grams of water. Shifts in your body water change what a scale estimates.

Bodyfat percent is like rent as a share of your income. If the rent and the income both drop, the share barely moves, even though you’re paying less.

What to do

• Watch the weekly average weight and the monthly waist. If both fall, fat is falling.
• Lift and eat enough protein, so the weight you lose is mostly fat and the percentage drops faster.
• Run the numbers with the fat or muscle calculator, using weigh-ins a month or more apart.