Does Muscle or Fat Weigh More?
Fat Size vs. Muscle Size
A pound of fat is roughly the size of a small grapefruit; one pound of muscle is about the size of a tangerine. In terms of appearance in our bodies, muscle takes up less space under our skin than fat. Multiply the size difference by ten pounds or more, and we see a dramatic effect on our physical appearance.
Why The Scale Is Wrong
As we've stated before, the scale is a terrible device for gauging how healthy or fit a person is. As we see in the above comparison, a 140lb woman who is mostly muscle will be much smaller in terms of physical size than a 140lb woman who has a large amount of fat due to the density of muscle vs. fat. We advocate putting the scale away and simply focusing on building muscle and lowering body fat through strength training and exercise.
Fat Doesn't Become Muscle
You can't convert muscle to fat. They are two entirely different substances that cannot be changed from one to the other. This small distinction is important to keep in mind as you continue toward your physical goals. As you burn more calories than you consume, your body will begin to use the energy reserves stored as fat in your body and you will begin to break down the fat tissue. Burning calories by strength training has an additional benefit in that it builds muscle, which further increases your body's daily calorie consumption.
Muscle Burns More Calories Than Fat
Muscle in a resting state burns roughly 10 calories per day. Fat only burns around 2-3 calories per day. It is a substantial difference that can be multiplied by adding pounds of muscle, helping to build up a surplus of calories burned throughout the day even at rest.