Muscle Weighs More Than Fat, Right?

Does muscle weigh more than fat?

No, it does not.

You have probably heard this and may have even said it. In your life: "muscle weighs more than fat." 

NOT true. 

People will argue with me about this, I get push-back on this, and you may have already given up reading this because I am wrong. But I am not. 

Let's look at this a bit more closely, and it becomes evident that this statement is wrong. 

A pound of muscle weighs? ONE pound. 

A pound of fat weighs? One pound. 

They are both one pound. 

Muscle does not weigh more than fat. 

Fat doesn't weigh less. 

But let me make it clear. 

Muscle is a much denser tissue. 

Fat is a "fluffy" tissue. Maybe not fluffy, if you've seen it. Think of it like feathers. 

A pound of feathers weighs a pound. The pound of feathers takes up a lot of space. It is fluffy.

Muscle is a solid tissue. Not solid like a rock, but again, you have seen it in meat. It is firm.

A pound of lead weighs one pound. Therefore, a pound of lead takes up relatively little space compared to feathers. 

When people say, "muscle weighs more than fat," that is an incorrect, inaccurate statement. 

Muscle takes up less space pound for pound than fat does. 

So, when people are changing their body composition, if they are gaining muscle mass and losing fat mass, the change is similar, losing a pound of fat, gaining a pound of muscle. But, still, the volume it takes up, and its space in the body are very different. And indeed, having more muscle mass and less fat mass will be healthier to a certain extent. Too low body fat isn’t a good thing.

Therefore, when people have a frustration that they are doing everything “right” and not losing weight, we ask how their clothes are fitting and how they feel. When fat and muscle mass switch places, nearly everything will fit differently including shoes, jewelry, and clothing.

Consider this: 

A person with 140 pounds and 30% body fat has 42 pounds of fat and 98 pounds of fat-free mass.

A person with 140 pounds and 25% body fat has 35 pounds of fat and 105 pounds of fat-free mass. 

Both weigh 140 pounds, but one of those people (or it could be the same person who has become more fit) is more compact now because of the increase in muscle mass and less fat mass. 

Note: Fat-free mass includes not just muscle but also bones, organs, fluid, and other tissues. And when someone is intentionally losing weight while also exercising and increasing muscle mass, most often, the bodies, organs, fluid, and other tissues will remain constant. 

Let's stop using this phrase. I'm on a mission to stop using this phrase, "muscle weighs more than fat." 

Just because something is repeated, even by celebrity personal trainers, doesn't make it accurate. 

And, while you may have known this all along and think most people do too? Trust me; this is a conversation I have had with people for over 20 years. Yet, most people I've engaged in this discussion with do not realize the differences.  

Let me know: did you know this already or is this new information?