Weight Gain
What happens inside the body when a person does not use up all of the food energy take in? The energy-yielding nutrients contribute the excess to body stores as follows:
- Carbohydrate (other than fiber) is broken down to sugars for absorption. In the body tissues, excesses of these may be built up to glycogen and stored, burned off as heat, or converted to fat and stored.
- Fat is broken down to glycerol and fatty acids for absorption. Inside the body, storage as body fat is very efficient.
- Protein is broken down to amino acids for absorption. Inside the body, these may be used to replace lost body protein and, in a person who is exercising, to build new muscle and other lean tissue. This protein must be functioning protein; excess protein is not passively stored. Excess amino acids have their nitrogen removed and are used for energy or are converted to glucose or fat, mostly fat.
- Alcohol is easily absorbed intact and is converted into body fat for storage.
Although 3 kinds of energy-yielding nutrients and alcohol may enter the body, they become only 2 kinds of enegry stores: glycogen and fat. Glycogen stores amount to about 3/4′s of a pound; fat stores can amount to many pounds. Note that when excess protein is converted into fat, it cannot be recovered later as protein because the nitrogen is stripped from the amino acids and excreted in the urine. So you see that if you eat enough of any food, whether it’s steak, chicken, brownies or baked beans, any excess will be turned to fat within hours. Weight can be gained as body fat or as lean tissue, depending mostly upon whether the eater is also exercising. Learn more here on the truth about abs.