Fat is deposited as adipose tissue in the body and perform essential functions in the body. Fats are composed of fatty acids and contain oxygen, carbon and hydrogen.
Fats are classified in to two types: saturated fat and unsaturated fat.
a) Saturated Fat: These have full number of hydrogen atoms. These are from animal sources. Example: butter, Ghee and vanaspati oil.
b) Unsaturated Fat: These contain one, two or more double bonds of fatty acids. These are extracted from vegetable sources. Example: Groundnut oil, soyabean oil, sunflower oil.
15-20% of total calorie requirements should be from fat
Animal sources: Fish, egg, meat, milk and milk products.
Plant sources: oil seeds (Groundnut, mustard, cotton seed and coconut oil), nuts.
• Supplies energy (9 kcals/ gm)
• Improve the palatability of food (flavor and taste)
• Supports body organs like liver and kidneys
• Provides insulation and thermoregulation against cold
• Provides essential fatty acids which helps in growth, promotion and maintenance of skin integrity
• Helps in formation of hormones in the body
• Helps in transportation of fat soluble vitamins
Digestion and absorption
There is no digestion of fats in mouth and very little in stomach. In the small intestine, presence of fat stimulates cholecystokinin and secretin which further stimulates pancreatic juice and bile. Food mixes with bile and emulsified. Pancreatic lipase hydrolyses and yields fatty acids and monoglycerides. These pass to small intestine and combined with intestinal lumen and absorbed in to blood stream.