The difference between skim and low-fat milk is the fat and fat-soluble vitamin content. Both skimmed and low-fat milk are regular milk that has been defatted. Regular milk contains about 3% to 4% fat, while skimmed milk contains less than 0.5% fat, and low-fat milk contains about 1.5% to 1.8% fat. Fat-soluble vitamins, such as Vitamin A and Vitamin D, are also removed to varying degrees in the defattening process. The fat content of skimmed milk is less than that of low-fat milk, and the content of fat-soluble vitamins is also reduced. However, ordinary milk is rich in high quality protein, calcium and other nutrients are basically the same. For the general population, it is recommended to drink whole milk, overweight or obese people, hyperlipidemia and other patients should choose to drink skimmed milk or low-fat milk, for people who are allergic to milk proteins, they should avoid dairy products.