What is dietary fat?

Dietary fat refers to the fats and oils found naturally in animal and plant foods, and those used in cooking, at the table, and added to processed foods. Dietary fat is made up of fatty acids. Fatty acid can be defined as a carboxylic acid with a long aliphatic chain and most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, from 4 to 28.

Dietary fat has five important functions:
*As a dietary source of energy
*For cell structure and membrane functions
*As a source of essential fatty acids for cell structures and prostaglandin synthesis
*As a vehicle for oil-soluble vitamins
*For control of blood lipids

Fat also contributes to the palatability of food and is important in cooking and food processing.

There are 2 types of fatty acids: saturates and unsaturated, which based on how the molecules in the fatty acid are joined together. All fats contain both saturated and unsaturated (mono- and polyunsaturated) fatty acids but are sometimes described as ‘saturated’ or ‘unsaturated’ according to the proportions of fatty acids present.

Dietary guidelines from the World Health Organization and the Dietary Reference Intakes recommend a total fat intake between 20 and 35% of total calories. The minimum of 20% is to ensure adequate consumption of total energy, essential fatty acids, and fat-soluble vitamins. This is to prevent atherogenic dyslipidemia (low high-density lipoprotein cholesterol (HDL-C), high triglyceride-rich lipoproteins) which occurs with low-fat, high carbohydrate diets and increases risk of coronary heart disease.
What is dietary fat?