What Are the Primary Sources of Energy in the Average American Diet?

There are three main nutrients that provide energy to the body: carbohydrates, fats and proteins. Any ingested source of energy can be classified into one of the three groups. Carbohydrates and fats can be broken down into further categories. Carbohydrates are broken down into starch, fiber and sugar. Fat can be broken down into saturated fat, monunsaturated fat and polyunsaturated fat. Fat is also the most energy-dense food per gram. While carbohydrates and proteins provide four units of energy (kcal) per gram, fat provides 9 kcal per gram.

Carbohydrates

• According to the Centers for Disease Control and Prevention, when averaged between males and females, 50 percent of American energy intake is from carbohydrates. This 50 percent is largely made up of grains and sugars. Since grain calories are mostly from starch, America's primary energy source can be said to be starch and sugar, with starch being ahead of sugar. America's consumption of grain has increased by 45 percent since 1970, and consumption of sugar has increased by 39 percent.

Fats

• America's second largest source of energy is fat. Fat provides 32 percent of energy in American diets. The percent of energy coming from saturated fat is 11 percent. The fat category can be further broken down to state that the second largest source of energy for the American public is polyunsaturated and monounsaturated fats. Since fat provides more kcal per gram of food ingested, fat is consumed much less in volume when compared to carbohydrates and even proteins.

Protein

• Protein is the least consumed source of energy in America. Protein provides 15 percent of total energy. While the consumption of carbohydrates has increased over the past years and fat has decreased, the amount of energy that protein provides has stayed the same. Even though the percentage of energy from protein has stayed the same (offset by a larger grain intake), the amount of beef the average American consumes is 57 lbs. more per year than compared to the 1950s.