United States
A sample nutrition facts label with instructions from the US FDA. [1]

In the U.S., the nutritional facts label lists the percentage supplied required in one day of human nutrients based on the average 2000 calorie a day diet. With certain exceptions, such as foods meant for babies, the following Daily Values are used (CFR 101.9(c)8(iv)). These are called Reference Daily Intake values and were originally based on the highest 1968 Recommended Dietary Allowances for each nutrient in order to assure that the needs of all age and sex combinations were met.[5] Notice that these are older than the current Recommended Dietary Allowances of the Dietary Reference Intake. For Vitamin C, Vitamin D, Vitamin E, Vitamin K, calcium, phosphorus, magnesium, and manganese, the current maximum RDA's (over age and sex) are up to 50% higher than the Daily Values used in labeling, whereas for other nutrients the estimated maximal needs have gone down.
Nutrient Daily Value for label highest RDA of DRI
Vitamin A 5000 IU 3000 IU
Vitamin C 60 mg 90 mg
Calcium 1000 mg 1300 mg
Iron 18 mg 18 mg
Vitamin D 400 IU 600 IU
Vitamin E 30 IU 15 mg (33 IU of synthetic)
Vitamin K 80 μg 120 μg
Thiamin 1.5 mg 1.2 mg
Riboflavin 1.7 mg 1.3 mg
Niacin 20 mg 16 mg
Vitamin B6 2 mg 1.7 mg
Folate 400 μg 400 μg
Vitamin B12 6 μg 2.4 μg
Biotin 300 μg 30 μg
Pantothenic acid 10 mg 5 mg
Phosphorus 1000 mg 1250 mg
Iodine 150 μg 150 μg
Magnesium 400 mg 420 mg
Zinc 15 mg 11 mg
Selenium 70 μg 55 μg
Copper 2 mg 900 μg
Manganese 2 mg 2.3 mg
Chromium 120 μg 35 μg
Molybdenum 75 μg 45 μg
Chloride 3400 mg 2300 mg

In certain cases this label is not yet required by law, so a list of ingredients should be present instead. Ingredients are listed in order from highest to lowest quantity.

The label was mandated for most food products under the provisions of the 1990 Nutrition Labeling and Education Act (NLEA), per the recommendations of the United States Department of Health and Human Services' Food and Drug Administration[6]. It was one of several controversial actions taken during the tenure of FDA Commissioner Dr. David Kessler. The law required food companies to begin using the new food label on packaged foods beginning May 8, 1994. (Meat and poultry products were not covered by NLEA, though the U.S. Department of Agriculture proposed similar regulations for voluntary labeling of raw meat and poultry.[2]) Foods labeled before that day could use the old label. This appeared on all products in 1995. The old label was titled "Nutrition Information Per Serving" or simply, "Nutrition Information".

The label begins with a standard serving measurement, calories are listed second, and then following is a break down of the constituent elements. Always listed are total fat, sodium, carbohydrates and protein; the other nutrients usually shown may be suppressed if they are zero. Usually all 15 nutrients are shown: calories, calories from fat, fat, saturated fat, trans fat, cholesterol, sodium, carbohydrates, dietary fiber, sugars, protein, vitamin A, vitamin C, calcium, and iron.

Products containing less than 5g of fat show amounts rounded to the nearest .5g. Amounts less than .5g are rounded to 0g. For example, if a product contains .45g of trans fat per serving, and the package contains 18 servings, the label would show 0g of trans fat, even though the product actually contains a total of 8.1g of trans fat.

Products that claim to be classified as low-fat and high-fiber must achieve uniform definitions between products of similar labels.

The nutrition facts label currently appears on more than 6.5 billion food packages. President Bill Clinton issued an award of design excellence for the nutrition facts label in 1997 to Burkey Belser in Washington, DC.

The FDA does not require any specific typeface be used in the Nutrition Facts label, mandating only that the label "utilize a single easy-to-read type style[3]," though its example label uses Helvetica.[4]

en.wikipedia.org/wiki/Nutrition_labeling