Does muscle weigh more than fat?

I remember learning about this concept in my human physiology class last year. My discussion class was having a debate on whether muscle weighed more than fat. In the article, it says that fat takes up about four times the the space of muscle tissue. No, muscle does not weigh more than fat because a pound is a pound, so they should weigh about the same. But in my class, I learned that muscle does contain more meat which should be heavier. This article was very interesting because it contradicts what I have learned previously.

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