OverviewReduced-fat milk refers to milk that has 2 percent of its fat from milk fat, skim milk often has the words "fat-free" on its label and dairy manufacturers can refer to 1 percent milk as "low-fat," according to U.S. Department of Agriculture guidelines. Understanding how the calories and fat in the milk you choose to drink can impact your health and weight may make a difference in whether you include reduced-fat milk into your diet.Calories and FatA cup of reduced-fat milk, or 2 percent milk, has 122 calories. The milk contains 4.83 grams of fat, which accounts for about 35.6 percent of the total calories. While your body needs healthy monounsaturated and polyunsaturated fats, more than 3 grams of the fat in 1 cup of reduced-fat milk come from unhealthy saturated fat. The American Heart Association advises adults to consume no more than 7 percent of their calories from saturated fat, as this type of fat raises your risk of cardiovascular disease.Calcium and ProteinMen need 56 grams of protein, and women need 46 grams of protein each day. A cup of reduced-fat milk gives you 8.1 grams of protein, or between 14 and 18 percent of your day's requirements. Protein in milk or other foods helps you build and sustain muscle development, and provides energy. Both men and women need about 1,000 milligrams of calcium a day before their 51st birthday, and after 51, calcium needs increase to 1,200 milligrams. Drinking 1 cup of milk provides you with 293 milligrams of calcium.Vitamin DMilk sold commercially in the U.S. is generally fortified with vitamin D. Vitamin D, found in just a few foods, helps your body absorb calcium and helps promote bone strength. Additionally, adequate amounts of vitamin D can help your immune system. Adults need 15 micrograms of vitamin D each day. A cup of reduced-fat milk provides you with 2.9 micrograms, or 19 percent of your daily requirement.Other NutrientsReduced-fat milk has more nutrients than just calcium, protein and vitamin D. The milk has 134 micrograms of vitamin A, which is about 17 percent of your daily requirement. If you are watching your cholesterol intake, a cup of milk contains 20 milligrams of cholesterol. The American Heart Association advises limiting your cholesterol intake to 200 milligrams a day, if your doctor tells you that you have high cholesterol, or if you have diagnosed heart disease. Reduced-fat milk also contains some of the B vitamins, including 1.3 micrograms of vitamin B-12.