Calculating the Calories

1. Start at the top of the label, just under the words “Nutrition Facts,” and look for the serving size. This is the amount of food that the nutritional information is based on.

2. Locate the servings per container, listed directly under the serving size. Calculate the number of servings you plan to eat. For example, if a can of soup lists 1 cup as a serving size, and you plan to eat 2 cups of soup, you plan to eat 2 servings.

3. Multiply the number of servings you plan to eat by the number of calories per serving. The calories per serving is listed directly underneath the serving information, under the heading “Amount per serving.” Calories come from fat, protein and carbohydrates. For example, the calories per serving in a can of soup are 120. Multiply that by 2 to get your total caloric intake of 240. A general guide to calories provided by the U.S. Food and Drug Administration states that 40 calories or less is low, 100 is moderate and 400 calories or more is considered high.

Calculating the Nutrients

1. Locate the first three nutrients beneath the calories. These are known as "limit nutrients" because the FDA recommends keeping these as low as possible. These nutrients are listed by weight in grams, and they include the total fat, cholesterol and sodium.

   Multiply the number of grams listed for each nutrient by the number of servings you plan to eat. The FDA recommends keeping your daily total fat intake under 65 grams, with less than 20 grams coming from saturated fat, based on a 2,000 calorie diet.

2. Locate the beneficial nutrients, located beneath the limit nutrients. These include the protein and total carbohydrates, broken down into dietary fiber and sugar. Sugars listed here reflect those that occur naturally in the product -- such as lactose sugar in milk -- and those that have been added to a product. Dietary fiber is found in complex carbohydrates and does not affect your blood sugar level.

3. Multiply the number of grams listed for each nutrient by the number of servings you plan to consume. Carbohydrates should provide 45 to 65 percent of your total daily calories.

Understanding Percent of Daily Value

1. Locate the footnote section of the label marked with an asterisk and the words “Percent Daily Values.” Your label may have a shortened version of a chart based on a 2,000-calorie diet. Some labels also include information for a 2,500-calorie diet. A 2,000-calorie diet is average for someone who is moderately active; your caloric needs may be higher or lower. The FDA offers this chart as a guide because many people consume more calories than needed without getting enough nutrients.

2. Make note of the percentage of daily value supplied by the product. Multiply the percent of the daily value by the number of servings you plan to eat. The FDA defines 5 percent or less of a nutrient as low, and 20 percent or more as high. For the nutrients you want to limit, which include total fat, saturated, fat, trans fat, cholesterol and sodium, choose foods as often as possible within the low limit. For beneficial nutrients such as calcium and dietary fiber, choose foods that offer high daily values.

3. Subtract the percent from 100 to calculate what is left of your daily allowance. For example, by consuming 2 servings of soup, you will have eaten 10 percent of your daily fat allowance, so you still have 90 percent to work with. The recommended daily allowance includes all foods and beverages consumed within a single day.

4. Compare another brand of a similar product to determine which one provides the least limit nutrients and the most beneficial nutrients for the same or similar amount of calories.