competitve atheletes and people on low-calorie diets ofter use more energy than they consume.?

Question

what happens to their body under these conditions? how can this be explained at teh molecular level?

Answer 1

Energy can be stored (fat, Carbohydrates are stored as glucagon to be made into glucose for the body at a later date), it can also be derived from the breaking apart of muscle tissue, as well as other bodily tissues.

Answer 2

They do replenish their body's energy stores but in emergency, yes, fat and protein (muscle tissue) can be converted to energy. They do make it up later.

Answer 3

You can't expend more energy than you've absorbed because:

x =! x + n

Conservation of energy .

It can't be explained at a molecular level because it's impossible.