1) Anabolic formation of lipid compounds in organisms or living cells; this includes fats, long-chain fatty acids, and oils.

2) De novo fat synthesis in the body. This includes the synthetic processes of fatty acids and subsequent triglycerides in the liver and the adipose tissue. Lipogenesis is regulated by numerous factors, including nutritional, hormonal, and genetic elements.

3) Formation of fat in the living body especially when excessive or abnormal.

4) The formation of fatty acids from acetyl coenzyme A in the living body.