Energy is what we all need to live and stay active. It is measured by kilocalories (kcal) and comes from all the food that we eat in varying amounts.
Different food types contain different levels of energy.
The environment that we live in is created and sustained by the energy from the sun. This energy is absorbed from the sun by plants and converted in to carbohydrate, fat and protein. Animals can't convert the energy from the sun but can use the energy created by plants and other animals.
Fat has the most energy per gram at 9 kcal per gram.
- Carbohydrate and protein have approx 4 kcal per gram.
- Fruit and vegetables will vary but generally have much lower levels of energy per gram.
The amount of calories (energy) you eat should be the same as you use up. Any excess calories that are eaten and not immediately used as energy will be stored in the body as fat.
- An adult man should aim to eat approx 2,500 kcals a day.
- An adult women should aim to eat approx 2,000 kcals a day.
If glucose from sugar is in the blood stream, the body will use this as a source of energy first. The body's next best choice of energy is from breaking down carbohydrates into glucose. If neither of these sources are available the body goes to its stores of fat which are converted for use.