The best time to drink milk is between meals, avoiding taking it with fruits and vegetables. The protein content in milk is relatively constant, around 3.0%, and traditionally there are two types of milk proteins, casein and whey protein. Casein, which accounts for 80% of the protein in milk, and whey protein, which accounts for about 20%. Casein contains a large number of phosphate groups, which enable calcium to interact and facilitate its absorption and utilization. Fruits and vegetables have some phytic and oxalic acids, and some dietary fiber, which are not conducive to calcium absorption, so choose to drink milk between meals.