Types of Milk

Milk is processed on the basis of the maximum content of fat and solid not fat (SNF) it would ultimately possess.

Standardized milk
Whole milk
Reduced-fat milk (2%)
Low-fat milk (1%)
Skimmed milk/non-fat milk

Standardized milk- This is made by combining buffalo milk and skimmed milk. The fat percentage is maintained at 4.5% while the SNF is 8.5%.

Whole milk: Whole milk must contain at least 3.25% milk fat and 8.25% milk solids by weight—which means it derives about 50% of its calories from fat. Because of this relatively high fat content, whole milk is best used only for infants and young children up to age 2. 

Reduced-fat milk (2%): This milk contains 2% milk fat. The percentage of milk fat refers to the percentage of fat by weight, and much of milk's weight is water. Once you subtract the water from 2% milk, for example, you're left with a product that contains 20% fat by weight; such milk actually derives 35% of its calories from fat. Drinking 2% milk is a good way to wean oneself from whole milk at first, but is too high in fat as a permanent choice, unless your diet is otherwise very low in fat.