Foods are prioritized based on their calorie sources

December 08, 2003|by Christine L. Moats

Anyone concerned about weight loss has more than likely discussed calories. We talk about calories all of the time, but what they?

According to Tim Higgins, clinical manager of nutrition services at Washington County Hospital, a calorie is a measurement of energy in the same way an inch is a measurement of length. A calorie is the amount of energy needed to heat up one gram of water one degree centigrade.

Calories are not physical components of food, but are a measure of the potential energy released when food is consumed and broken down during digestion. When digested, food yields heat and forms compounds that can be used immediately by the body for energy or stored and used at a later time.

"The energy derived from calories is used to run all of the functions in our body, including fueling muscles like our heart," noted Higgins.


Calories released during the digestive process are derived from the breakdown of three primary components of food - carbohydrates, fats and proteins. Alcohol, a refined carbohydrate, can also provide calories. Foods may also contain other essential compounds, such as vitamins, minerals and water, but these do not provide calories.

The amount of calories released during digestion varies from one food to another, depending on the proportion of proteins, fats and carbohydrates. Carbohydrates and protein provide 4 calories per gram, fat provides 9 calories per gram and alcohol provides 7 calories per gram. Fat produces more than twice as many calories per gram as carbohydrates and protein.

The U.S. Department of Agriculture food pyramid groups and prioritizes foods based on their calorie sources. Foods with similar amounts of carbohydrate, fat and protein are grouped together in the pyramid. At the base of the pyramid are breads and starches, which many nutritionists say should make up the bulk of a balanced diet. The majority of calories in these foods come from carbohydrates. Foods in the meat group produce most of their calories from protein or fat.

When the topic of calories comes up, think potential energy for the body. Think calorie source. After understanding that calories are a measure of energy, perhaps the question of how to maintain nutritional balance can be answered more easily.

This column will discuss nutrition for the next four weeks. Look for more information on balancing calories and weight loss.

Christine L. Moats is a wellness coordinator at Washington County Hospital.

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