To figure out the percentage of calories from fat, you must take the number of calories from fat and divide that number by the total number of calories per serving which is typically a much different amount. A label may state that a product is reduced fat or reduced sodium. However it does not mean that that product is low in fat or sodium. Consumers should be aware that the amount of sugar listed on a label does not make a distinction between sugar that is naturally present in a food and sugar that has been added. For example, a serving of fat-free milk will typically list the grams of sugar to be about 13, but no sugar was added to the milk.
Milk just happens to naturally contain lactose, one type of sugar, often referred to as milk sugar.
This does not mean you should avoid milk. Sugar may not always be a bad thing. Milk provides plenty of other important nutrients. It is always a good idea to look at both the grams of sugar and the ingredient list. Ingredients are listed according to weight.