Submitted by Thiruvelan on Wed, 11/23/2011

Fat is one of the crucial nutrients required for normal body function. Fat not only provide energy; it also supports other nutrients to do their function.

What are fats?

The fats are usually having three fatty acids joined with a glycerol. Fats are either liquid or solid form at room temperature; its form is deciding by its structure and composition. In common, practice the word’s oil, fat, and lipids all refers to fats; however, in actual:

  • oil refers to fats that are in a liquid form at room temperature
  • fat refers to fats that are in a solid form at room temperature
  • lipid refers to fats that are either in a solid or a liquid form at room temperature

Dietary Fats

Fats are available from both animals (lard, fish oil, and butter) and plant (peanut, soya bean, sunflower, sesame, and coconut oils) sources.
Fats can provide almost 2.5 times more energy than that of glucose (carbohydrates). Fat can provide 9 calories per gram.

Fat Classification

Fats are broadly classifying into two groups; they are:

Saturated fats have no double bonds and are in a solid form at room temperature. Too much intake of saturated fats may increase blood cholesterol level, particularly bad (LDL) cholesterol level. Therefore, it is considering as bad or unhealthy fat.

Unsaturated fats have at least one double bond and are in a liquid form at room temperature. It tends to lower bad (LDL) cholesterol and raise good (HDL) cholesterol. Therefore, it is considering as good or healthy fat. In general, nuts, vegetable oils, and fish are the common sources of unsaturated fats.

  • Monounsaturated - dietary sources are Nuts, Vegetable oils (Canola oil, Olive oil, High oleic safflower oil and Sunflower oil) and Avocado
  • Polyunsaturated fats

Polyunsaturated fats can be further divide into two types; they are:

  • Omega-6 polyunsaturated fat provides an essential fatty acid that our bodies needs, but cannot be able to make. Dietary sources are soybean oil, corn oil and safflower oil.
  • Omega-3 polyunsaturated fat provides an essential fatty acid that our bodies needs. Dietary sources are soybean oil, canola oil, walnuts, flaxseed and fish (trout, herring, and salmon)

Cholesterol is a type of fatty substance mostly found in animal meats, poultry, egg yolks, and whole milks.

Trans-fats are a special class of fat, modified by human to improve the flavor and shelf life of fats. Trans-fats are tending to increase bad (LDL) cholesterol and decrease good (HDL) cholesterol. Examples for trans-fats are pastries, vegetable shortening, margarine and other hydrogenated vegetable oils.

Do fats make us fat (obese)?

Over the years, there is a misconception that eating fats can lead to obese or over weight. However, in reality, fats we eat is not the cause for over weight, instead only the excess calorie that we consume than needed is the cause for the over weight.

Therefore, whenever we eat more calories than we do burn, then these extra calories are converting into fat and store for the future requirements. The excess calories that we eat are in the form of fat, protein, or carbohydrates.

Importance of Fats

Even though fats have gained a bad reputation, still some fats are vital for survival. Many dietary institutions emphasize 20 to 30 % of calorie needs should be fulfilled by the fats.

  • Energy - Fat is an important source of calories; it provides 9 calories per gram that is more than two times the amount that is providing by carbohydrate or protein (which provides only four kcal of energy per gram).
  • Brain - Fat provides the structural components for brain’s cell membranes and myelin sheath (the fatty insulator that surrounds each nerve fiber, helps it to a carry a faster nerve impulse).
  • Vitamins - Fats play an important role in the absorption of fat-soluble vitamins such as vitamins A, D, E, and K.
  • Skin - provides healthy skin (deficiency may cause dry, flaky skin), nail, shiny hair, and help regulate body temperature that is why a lean person with low fat reserves under their skins tends to be more sensitive to cold.
  • Our body needs fat to make varies building blocks required for hormones to immune function.
  • Fat is required for every cell membrane in our body; it helps carry nutrients and metabolites across cell membranes.
  • Fats insulate our body organs against shock by providing some cushion effect.
  • Fatty food stays longer in the stomach and prevents hunger soon after meals.