Fact Check

What Weighs More: a Pound of Muscle or Fat?

It's time for a quick math lesson.

Published July 18, 2023

Updated July 19, 2023
Comparison of a fit and obese male, computer illustration. ( Getty Images)
Comparison of a fit and obese male, computer illustration. (Image Via Getty Images)
Claim:
A pound of muscle weighs the same as a pound of fat.

A simple math problem garnered over 4,000 upvotes on Reddit this week and sparked hundreds of comments, many of which were arguing about the answer. 

Last week, a Reddit user posted a screenshot to r/facepalm, a subreddit dedicated to the things that exasperate and astound us, of a Healthline article. The r/facepalm forum is often use to poke fun at hubris or ignorance; for example, the tourists defacing the ancient ruins of the Roman coliseum, or the kid who attempts a backflip and lands face-down on the floor

In this case, however, the "facepalm" is arguably the post itself. 

According to science
by u/Linux_B in facepalm

It appears as if the poster sought to mock Healthline's claim, which is that a pound of fat and a pound of muscle are equal. However, it's true: a pound of muscle and a pound of fat weigh the same thing. They both weigh 1 pound. 

The confusion often comes from a question of volume as opposed to weight. Muscle is more dense (i.e., has more mass per unit of volume) than fat. This is why, for example, an athlete building muscle may see a decrease in their waistline but a plateau on the scale. Muscle takes up less space than fat, but space is not an issue when weighing an object — its mass is. Weight, which is a measurement of the force of gravity acting on a given mass, is not affected by volume, just the number of atoms in a given substance or object.

As several commenters pointed out, it's highly evocative of "What's Heavier?", a viral segment from Scottish sketch comedy series, "Limmy's Show."

For those still confused, it also provides a good visual explanation of the way the math works. 

Sources

"Does Muscle Weigh More Than Fat? The Truth About Body Composition." Healthline, 8 July 2020, https://www.healthline.com/health/does-muscle-weigh-more-than-fat.

Limmy's Show: What's Heavier? | What's Heavier? A Kilogramme of Steel or a Kilogramme of Feathers? (From Limmy's Show, Now on Netflix) | By Limmy | Facebook. https://www.facebook.com/LimmyDotCom/videos/limmys-show-whats-heavier/10150732976784957/. Accessed 18 July 2023.

"Steel Is Heavier Than Feathers." Know Your Meme, 9 May 2018, https://knowyourmeme.com/memes/steel-is-heavier-than-feathers.

Updates

July 19, 2023: Updated to clarify the distinctions and interrelationships between volume, weight, and mass.

Sarah Baum is a former reporting fellow for Snopes.