What happens to excess energy that is taken into the body?

Answer 1

This depends on your levels of activity and the dietary source. If you are very active this excess energy will be stored in the body as glycogen - a ready made fuel source, however when glycogen stores are replete any excess nutrition will be converted to glucose and stored as fats/lipids in something called adipose tissue. A store of fat is essential to live, and is also a secondary source of high energy when carboydrate or glycogen stores are depleted, but should only make up 30-35% (max) of daily kcal count. The concept of energy balance whereby energy consumed is equal to energy expended will maintain weight at a stable level, so hard training will require significant increases in carbohydrate intake to supply energy.