‘Lipid’ was coined by biochemist Bloor in 1943 in Germany encompassing the main class of foodstuffs and tissue components. ‘Fat’ is used as a synonym for “lipid”. Fats are hydrophobic.

Lipids are divided into three types:

– Simple lipids such as Triglycerides and Triacyglycerols
– Compound lipids such as Glycolipids and Phospholipids
–  Derived lipids such as Fatty acids, Steroids, Alcohols, Terpenes, Carotenoids mono/diglycerides

Triglycerides: Most abundant lipids and are referred to as neutral fat and make up about 98% of total dietary fats.  The other 2% include phospholipids, cholesterol and its esters. In animals, fat cells contain mostly triglycerides.

Cholesterol: Steriods containing hydroxyl groups are called sterols. Animal sterols or zoosterols include cholestanol, coprostanol, cholesterol. Phytosterols or plant sterols include spinasterol, ergosterol, stigmasterol.

Cholesterol is commonly thought to be a major cause of heart disease and comes in 2 variants:Low Density Lipoprotein (LDL) and High Density Lipoprotein (HDL).Fegetables do not contain cholesterol and hence claim by manufacturers about low cholesterol oil are nonsense. Animal oils such as butter do contain cholesterol. Most cholesterol is synthesized by the body, casting doubt on claims that dietary cholesterol is bad for health.