The nutrition facts panel tells you what a serving size looks like, how many calories are in a serving, and how many grams of carbohydrate, fat, and protein are in that serving. It also highlights cholesterol, sodium, potassium, iron, Vitamin D, and calcium content. Some of these quantities are also expressed as a percentage, meaning that one serving of the food in question provides a certain percentage of the DV (daily value) for that nutrient. These numbers are based on a 2,000 calorie per day diet.