Originally Posted by
Someday_RN
I am not sure what I am saying either so that is why I asked the question.
It is posited that a pound fat contains 3500 calories. So if in a week there is a 3500 calorie deficit, exclusively from fat, there should be a 1 pound loss of fat. Muscle can also be broken down for an energy source. So how many calories does one pound of muscle provide?
What I am thinking is, that when there is a caloric deficit creating a weight loss, calories are being used from sources other than fat. If muscle provides less calories per unit weight then it is possible to loose more then one pound a week with a 3500 calorie deficit. Reason being, is that pound for pound muscle provides fewer calories.
So if one was to burn through 3500 calories a week of muscle would there be a greater weight loss?
The following quote is from the link you posted.
IMO This explanation suggests that weight loss is strictly fat, and that a calorie deficit will only result in fat being lost. What would be the weight 3500 calories of muscle?
First of all, you don't have a choice to burn fat or burn muscle ... that's your body's decision.
Secondly, when you go into a deficit situation, your body looks first at any stored carbohydrates in your liver. If you've been eating well, you should have about 2000 calories stored there. So your body uses that up. If the deficit situation continues (think starvation diet) then your body looks for any stored fats, and most of us have some of that around in various locations on our body. So then your body converts your fat to calories and uses that up. Finally, if the deficit continues (still starving - no, or next to no food) the body looks for what else it can use and starts taking from the muscle.
If you operate on a deficit of 500 calories per day, over the first few days your body will use up what is in your liver. This could be why sometimes your weight remains the same for the first week or two when you start an exercise/diet program. Then your body will start converting stored fat to calories and using it. But because a deficit of 500 calories per day isn't excessive, and most of us have more than 1/7 of a pound of fat on us, your body will not touch your muscle.
If, however, you were to go on a starvation diet, or less drastic, if you were to stay with the 500 calorie a day deficit, until you reached your ideal weight, and then until you were underweight, and still continued to operate on a 500 calorie a day deficit after that, then your body might have to start using muscle because there's nothing else left.
Did that help explain it all a bit more?