Calories as Fuel
Burning calories is a natural part of your body’s metabolism. The body’s metabolism comprises of thousands of different chemical reactions, some of which release energy and some of which use it. In general, energy is created from the breakdown of nutrients such as glucose (carbohydrates) and fats. These nutrients are found in the food we eat. A calorie is the amount of energy that is released as heat when these nutrients are metabolized. A certain amount of energy is needed to maintain basic body functions, such as breathing, heartbeat, body temperature, and muscle contraction.
The amount of energy needed to sustain these basic functions is referred to as the basal metabolic rate (BMR). This rate will vary from person to person and depends upon many factors including age and body composition. People who are more muscular (i.e. have a lower percentage of body fat) require more calories to maintain their BMR. Muscle uses more calories to maintain itself than fat. The average human stores about 1,500 calories in muscle and another 300 calories in the liver. Extra calories are stored as fat. However, fat is processed slowly in the body. If you continue to eat more calories than your body needs, it will continue to store the extra calories as fat. The capacity of the human body to store fat is almost unlimited. People who are obese can store almost a million calories within their body. Fat is a major source of fuel for exercising muscles. Therefore, some fat is necessary. As muscle deplete their fuel reserves, they are replaced by fat from the body’s fat stores.
Nutrition and exercise play a major role in “fuel” use and overall good health. A fit body is strong and efficient and can handle more stress. Understanding nutrition, healthy diet, and how foods are broken up into “fuel” will help put you on the road to better health.
Carbohydrates are “fast” burning. They are easy for the body to convert to energy. However, they are not stored well. A diet high in carbohydrates may leave you feeling hungry. Balance is important. In general, carbohydrates are things that are grown (rice, wheat, oats, fruits, and vegetables).
Proteins are “medium” burning fuels. Proteins are important elements for muscle and tissue building and repair. Milk is a good source of protein. Meats (beef, pork, and poultry) are also a good source of protein; however, many are also high in fat. Fish, dairy products, legumes, nuts, and seeds are also good sources of protein.
Fats are “slow” burning fuel. Each ounce of fat you eat has twice the calories of an ounce of carbohydrates or proteins. This is why “fat” foods are harder to “burn-off”. Fat is important. It aids digestion, helps keep skin and hair healthy, and is an important “fuel” source.