Does Muscle Weigh More Than Fat? (And Why It Matters)

We've got the answer to your burning questions.

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Does muscle weigh more than fat? This question can't help but read a little like that timeless children's riddle of what weighs more: a pound of lead or a pound of feather?

Isn't a pound a pound? Shouldn't a pound of anything weigh as much as a pound of anything else? Well, in a sense, but it's a little more complicated than that. If you're asking yourself this same question, whether for scientific reasons, fitness-related, or because you're genuinely curious, there are a few factors at play here.


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1. Muscle is denser than fat.

“A pound of muscle weighs the same as a pound of fat,” says Robert S. Herbst, a personal trainer, weight loss and wellness coach, and powerlifter. However, it’s not all that simple: “Since muscle is denser than fat, however, a pound of muscle takes up less space, so a muscular person can weigh the same as an obese one but look trimmer.”

2. It's not just about the scale.

People on a diet who are lifting weights to burn fat should ignore the scale. They may be adding muscle while losing fat, so the number on the scale may not change that much.


“The question is whether they pass the eyeball test and look better, with a smaller waist and broader chest and shoulders,” advises Herbst.

3. You're losing mass, even if you're not losing pounds.

That's why the numbers take so long to decrease, even when we're showing successes like our clothes fitting better. When we lose weight, the reason it takes so long for the pounds to fall off the scale is because fat does not weigh much.

According to Dr. Ryan Neinstein, a plastic surgeon and liposuction specialist at Neinstein Plastic Surgery“It is not very dense, while muscle is very dense.”

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4. Muscles take up less space than fat.

One pound of feathers is the same as one pound of iron, but they occupy a different amount of space.

“Lean muscle tissue is denser than fat,” says Dr. Thanu Jeyapalan, Clinic Director at Yorkville Sports Medicine Clinic. This means for the same amount of weight, muscle tissue will occupy less space in your body than fat, making you look smaller. “1L of muscle, which is the space occupied, weighs 2.3 pounds, while the same amount of fat weighs roughly 2 pounds.”


5. You may add muscle as you drop pounds.

“If you've recently started a weight training program and your weight on the scale has stayed the same or even gone up, it may be an indication that your body is adding lean muscle tissue, which is a big positive in your health for the long run,” says Dr. Jeyapalan.

6. Visual is sometimes different than internal reality.

“In liposuction and body contouring, we remove stubborn fat which gives a big visual change, but not necessarily a huge change on the scale. Think about removing feathers that fill a room. The room will look very different but the feathers will not weigh that much,” Dr. Neinstein suggests.

7. In the end, it really is about activity and calories.

“When muscle bulked individuals decrease either their activity level or caloric intake, they can lose weight dramatically, because the body preferentially breaks down the muscle for energy,” Dr. Neinstein says.


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Aly Walansky is a NY-based lifestyles writer. Her work appears in dozens of digital and print publications regularly. Visit her on Twitter or email her at