Fats are a food group description that includes a number of substances consumed in the typical diet. In the narrowest chemical sense, fats are a compound form of various kinds of fatty acids, found in various kinds of animal fats, vegetable fats, and oils. The type and the quantity of fats consumed by the human body are a very important factor in both athletic performance and in human health.
Fats, along with carbohydrates and proteins, form the cornerstones of daily human nutritional needs. Although the ratio between each group may vary depending on individual circumstances, a general relationship of 60-65% carbohydrates, 12-15% proteins, and less than 30% fats is accepted as a healthy one. All of the food groups are possible sources of fuel production within the body. It is important to distinguish between fat intake, the simple act of the consumption of the food group, and fat oxidation, the process by which fats are converted into an energy source.
There are different kinds of fats. Saturated fats are most commonly contained in animal meats, dairy products, and cooking ingredients such as shortening. These fats are of little benefit to the manner in which the body functions. Saturated fats are linked to the production of low density cholesterol, an agent generally known as a cause of clogged and thickened arteries, which is a condition called arteriosclerosis.
Unsaturated fats are found in food sources such as olive oil, many nuts, canola products, and soy. These fats have a protective quality in that they contain the fatty acids necessary to the absorption of vitamins A, D, and E into the body. Unsaturated fats have two subdivisions, polyunsaturated and monoun-saturated fats. Polyunsaturated fats contribute essential fatty acids, so named because they cannot be produced by the body internally. There are three types of essential fatty acids, including linoleic acid (such as omega-3), arachnoidic acid, and linolenic acid. Each of these acids is beneficial to the function of various systems in the body, particularly the reduction of low density cholesterol and the function of the central nervous system.
Trans fatty acids, commonly known as trans fats, are a substance that rose quickly to dietary prominence after the year 2000. Trans fats are exceedingly rare in natural foods, but are common in vegetable oils that have been hydrogenated, meaning they are converted into a solid form—such as a block of shortening. Like saturated fats, trans fats provide little nutritional value to the function of the body; they are a proven contributor to the formation of cholesterol in the bloodstream. Trans fats are of particular concern because smaller amounts of trans fats will contribute to disproportionately greater low density cholesterol formation in the bloodstream.
The human body does not discriminate in the manner in which fats are consumed; fats generally take longer for the body to digest than carbohydrates. When not processed into fatty acids, fats will be stored in adipose tissues, located either under the skin or in and around the internal organs. Adipose is derived from the Latin for fat.
While fat is an essential component of a healthy diet, the consequences of the consumption of foods with too great a percentage of "bad" fats are not limited to less than optimum physical performance. Certain types of the "healthy" fats contain a considerable number of calories; the conscientious dieter must balance not only the value of the potential fat-containing foods, but also the richness of the healthy fat products. As an example, canola oil is a healthy alternative to animal lard; the caloric value of the canola oil is a consideration separate from the presence of healthy fats.
For a highly trained athlete, fat consumption in the 25% range of total foods consumed (which would be suitable for a typical healthy adult) may not necessarily satisfy the needs of elite athletic performance. Each determination will itself be entirely specific to the needs of the sport or a position played within the sport. Team sports such as American football create a wide variety of physical demands; a fast wide receiver may weigh 190 lb (85 kg), with a percentage of body fat of 7%, whereas a lineman may weigh 290 lb (130kg) and carries a percentage of body fat of 15%, needed to support the energy demands of significantly greater muscle mass. As a general rule, an athlete will be able to maintain a lesser percentage of body fat through lesser quantities of fat in the diet, subject to the demands placed on the body through training.