The human body must produce large amounts of energy for all physical and mental activities.
But where does this energy come from? The answer is both simple and complex. The energy produced by the body comes from the foods we eat. This energy is obtained from the basic macronutrients in food â€” carbohydrate, fat and protein. Though many foods contain all three, thereâ€™s usually a predominance of one of these in each food.
Consider the following examples:
- Carbohydrates are predominant in bread, sugar, rice, pasta, fruit and fruit juice, cereal.
- Fats are dominant in oil, butter, cheese, egg yolk.
- Protein is highest in meat, fish, poultry, eggs, cheese.
The majority of energy is produced from two of these food groups â€” carbohydrate and fat. Only a small amount, up to 15 percent of total energy, is produced from protein (by conversion of certain amino acids into glucose).
All three macronutrients are converted into energy in two steps. First, they are broken down in the intestine and absorbed into the blood as glucose from carbohydrates, fatty acids from fats, and amino acids from protein.
In the second step, the blood ultimately carries these elements to the cells, where the molecules of glucose, fatty acids and amino acids are further broken down.
Carbohydrates, fats and proteins each have different amounts of hydrogen molecules, and, therefore, potential energy. Fats have by far the most hydrogen, one reason we can get much more energy from the fats in food. Fats can actually provide more than twice the potential energy you get from either carbohydrates or protein.
The more energy you derive from fat the better your fitness, health and human performance. By improving your fat-burning system, youâ€™ll improve metabolic efficiency and have more physical and mental energy. In addition, your body will store less fat, and youâ€™ll maintain a more stable blood-sugar level because you wonâ€™t need as much sugar for energy.
When you donâ€™t produce the required amount of energy from fat, your body instead relies too heavily on sugar, usually producing fatigue. This common symptom, fatigue, is one of the most common complaints heard by doctors. It comes in physical and mental forms, or in a combination of both.
Physical fatigue may strike at a particular time of the day, or it may make you feel exhausted from the time you awaken. You may feel you donâ€™t have the energy to do extra chores, go out at night or even get up in the morning.
Mental fatigue is also common, making it difficult to think clearly or make decisions. This can affect anyone from students and executives to children and adults at all ages. To avoid fatigue and instead access unlimited energy from your fat-burning system, two things must occur.
First, you need to develop and utilize the bodyâ€™s aerobic system.
Second, you need to provide that system with the proper fuel in the form of food.
In general, as fat-burning improves the body is able to correct many of its own problems. The bottom line â€” more fat-burning improves health, fitness and human performance.