Quite obviously by removing fat from whole milk. But how does one get rid of fat? The traditional method is to let milk sit in the fridge and wait until the cream rises to the top and creates a solid layer. Then, as you gather the cream, you will be left with milk with a lower percentage of fat. You will probably need to repeat this process a couple of times to achieve truly skimmed milk, but in essence, that’s how you make low-fat milk.