Muscle Weight vs. Fat Weight

I noticed this post of Peg's in another thread and I thought it was an interesting idea that deserved some discussion. I've heard people say (and I've even said it in this forum) that when I started to work out I would "gain weight because muscle weights more than fat" but how accurate is that really?

(Side Note to Peg: I hope I don't offend or embarrass you by creating a separate thread to discuss this. I just thought your post was thought-provoking.)

Peg's Post (truncated)
... I had to do some searching about people saying muscle weight more then fat well it doesn't is weight the same.

"Stop being so obsessed with body weight and start paying attention to body composition. How much body fat do you have compared to muscle?" A woman weighing 150 pounds with 19% fat will look much smaller (and be much healthier) than a woman at 150 pounds with 35% fat. They weigh the same, yet the composition is different. Because muscle is more dense than fat the person with less fat and more muscle will look smaller."
I just pulled them off of a medical journal for us.

So if you are working out you also need to measure yourself. ...

My Thoughts:
I think that when people first start working out they say that they've gained weight "because muscle weighs more than fat". I think what really happens though is that they are gaining muscle that they didn't have before. It's not necessarily that muscle weights more than fat, it's that they've increased their weight because they have increased their muscle mass. Just like when you gain more fat, you also gain weight.

I'm just wondering if muscle is more dense than fat, doesn't that mean that muscle really does weigh more than fat? If you weighed a 1 inch cube of fat and a 1 inch cube of muscle would they really weigh the same? Lead is more dense than aluminum so a 1 inch cube of lead would weigh more than a 1 inch cube of aluminum. Re-reading the quote, I'm thinking that it's saying that the weight of the two people is the same, not that fat and muscle weigh the same.

Anyway, the point of Peg's post was that body composition and how many inches you've lost off your waist is a lot more important then what the scale says and I agree with that completely.

Alright, that's all I have to say. Let me know what you think. (or completely ignore me as you wish )

I hope I didn't offend anyone about muscle weighting the same a fat. I was watching the biggest loser it was about week 2 and no one had lost any weight some had gain and out of one's mouth came you gain muscle so that's why you didn't lose or you gain. Bob and Jillian looked at each other and said no that is not the case. So with that statement I had to look it up and to make sure what they were talking about. Because I've always heard when you exercise you will turn your fat into muscle and sometime you gain weight durning the course of your workout and your weightloss. So that's why I started to measure my hips and waist because I wasn't losing but I was seeing a change in my body but not on the scale at the beginning of my weightloss.
Please don't take this offense I don't like making enemys in chat places. Peg

@Peg - I don't think anyone is offended by your post (I'm certainly not), I just wanted to make sure I didn't cause any problems by quoting you out of context without your permission. I just thought the topic deserved more discussion.

I've very rarely watched the Biggest Loser so I don't know much about Bill and Jillian or the episode you are talking about so take what I say next with a grain of salt. I'm just thinking that the people on there are trying to lose a lot of weight and are doing pretty intensive things to lose that weight (more than you or I are necessarily doing). In that case, no matter how much fat weighs versus muscle (or if they weigh the same), they should still be losing weight. If they aren't losing weight then there might have been something else they weren't doing that they should have been doing so that may be what Bill and Jillian were referring to.

I know for me personally, I don't really have much extra fat or weight to lose. I'm trying to exercise more to get healthy so I actually expect that I might gain weight in the form of muscle. If I'm not gaining weight, then I might not be exercising as much as I should be.

Anyway, that's just my two cents.

Lady, you are correct about the Biggest Loser contestants. For the amount of training they do, they should lose weight every week. On occasion, when somebody doesn't lose or even gains a little, the trainers will find that they haven't been eating enough. They have it in their heads from years of dieting that they need to eat less to lose weight. In their situation though, they need to make sure they eat enough to give their bodies the fuel it needs to make it thru the workouts.

PS It's BOB, not Bill!

Oops! I can't even use the excuse that I don't watch the show since Peg had the right names listed. My only excuse is that I must have combined the B from Bob and the ill from Jillian to make Bill.