The Food We Eat There are 3 primary food sources, carbohydrates - (CHO’s), fats and protein. CHO’s are converted to glucose in the body and provide the most readily available source of energy. CHO’s which are not required immediately for energy are stored in the body. About 500g is stored in the liver and skeletal muscles and once these areas are full, the liver converts the glucose to fat and stores it in the adipose tissue. Fats, which constitute the largest energy reserve in the body, are often not used as the primary energy source as they are harder to break down than CHO’s. Specific exercise conditions are required if fats are to be utilised as the primary energy source.
Proteins are essential for the building and repair of lean body tissues and as such are utilised as a last resort energy source, such as starvation conditions, when CHO’s and fat stores are completely depleted.