Cooking oils (liquid) and solid fats together are referred to as fats. Fats contribute to texture, flavor and taste and increase the palatability of the diet.

Fats are essential for meeting some of the nutritional needs like essential fatty acids (linoleic n-6 and alpha-linolenic n-3) and serve as rich sources of energy. Fats also promote the absorption of the four fat-soluble vitamins (A,D,E and K), Therefore, fats should be consumed, in moderation.

Dietary fats can be derived from plant and animal sources. Fats that are used as such at the table or during cooking (vegetable oils, vanaspati, butter and ghee) are termed as “visible” fats. Fats that are present as integral components of various foods are referred to as “invisible” fat.

The total fat (visible + invisible) in the diet should provide between 20-30% of total calories. Adults with sedentary lifestyle should consume about 25 g of visible fat, while individuals involved in hard physical work require 30 - 40g of visible fat. Visible fat intake should be increased during pregnancy and lactation to 30g. Diets of young children and adolescents should contain about 30-50g/day. However, ingestion of too much fat is not conducive to good health.

All fats in foods provide mixtures of three types of fatty acids, which are the “building blocks” of fats. Fatty acids are the primary constituents of all dietary fats. Based on their chemical nature, the fatty acids are broadly grouped as saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA).

Fats from coconut oil, vanaspati, animal fats (ghee and butter) and animal foods like milk, milk products and meat provide saturated fatty acids. Saturated fatty acids are known to increase serum total and LDL-cholesterol levels, reduce insulin sensitivity and enhance thrombogenicity and increase CVD risk. Therefore, SFA intake should not exceed 8-10% of total energy.

During hydrogenation, the liquid oils become solid because the mono and polyunsaturated fatty acids are converted into saturated fatty acids and isomers called trans fatty acids. Current evidence indicates that saturated fatty acids and a high intake of trans fatty acids may increase the risk of heart disease. The intake of trans fatty acids should not exceed 1% of energy intake. Example of Trans fat is Vanaspati/ Dalda.

Unsaturated fats are considered as good fats they are liquid at room temperature and are considered beneficial fats because they can improve blood cholesterol levels, ease inflammation, stabilize heart rhythms, and play a number of other beneficial roles. Unsaturated fats are predominantly found in foods from plants, such as vegetable oils, nuts, and seeds.

There are two types of unsaturated fats monounsaturated (MUFA) and polyunsaturated fats (PUFA). Monounsaturated fats are found in high concentrations in Olive, peanut, canola oils, Avocados, almonds, hazelnuts, and pecans, pumpkin and sesame seeds. whereas polyunsaturated fats are are found in high concentrations in Sunflower, corn, soybean, and flaxseed oils, Walnuts, Flax seeds, Fish.

Omega-3 and Omega-6 are simple PUFA, which are present only in plant foods. Omega-3 increase insulin sensitivity, increase peripheral glucose utilization and decrease adiposity and hence are anti-atherogenic. Omega-6 decrease plasma cholesterol.

Vegetable oils like Red palm oil, Palmolein, Groundnut oil, Rice bran oil, Sesame seed oil, Sunflower oil, Cottonseed oil, Corn oil and Soyabean oil are a good sources of Omega-6, whereas Rapeseed oil, Mustard oil and Soyabean oil are a good sources of Omega-3.