How to Read Food Labels
Food packages generally have two types of consumer information required by the Food and Drug Administration (FDA). The Nutrition Facts section defines a serving size and describes the weights of macronutrients (fat, carbohydrate, protein) in a serving and the percentages that these macronutrients represent of the daily Recommended Dietary Allowance (RDA) for a 2000-Calorie diet. Additional information may be provided for specific minerals, vitamins, or other components of interest such as cholesterol. The second type of consumer information is the List of Ingredients which contains the basic components of the product in order of decreasing weight. Since the basic components must be listed, products containing ingredients consisting of several components must list the components in parentheses. A breakfast cereal containing crystallized ginger must list it as "crystallized ginger (ginger root, sugar)". Manufacturers sometimes add explanatory notes about an ingredient, e.g., "BHT (a preservative)".Food labels have a lot of technical information that is hard to interpret. We will compare the nutrition labels of raw sunflower seeds from two stores to try to figure out the differences. Weight ratios of fat, carbohydrate, and protein of 2:1:1 to 3:1:1 are very typical for nuts and oil seeds.
The most obvious discrepancy in these labels is the serving size of 28g for the Whole Foods seeds vs. 33g for the Trader Joe's seeds, both of which have 190 Calories per serving. It is unlikely that a five-gram (15%) difference in the serving size would have a negligible effect on the total calories. We also notice that the Whole Foods seeds have three times the amount of fiber as the Trader Joe's seeds, and Trader Joe's seeds have no sugars whereas the Whole Foods seeds have 1 gram of sugars. Aren't all sunflower seeds the same? How reliable are these "Nutrition Facts"?
Let us start with a simple check to see if everything adds up. The Whole Foods serving size is 28g, but if we add 17g of fat, 6g of carbohydrate, and 7g of protein the total is 30g. Oops! It is not unusual for the sum of the components to be slightly different than the whole due to rounding errors and unlisted components, but it is abnormal to have the components exceed the total serving size by 2 grams (7%).
The Trader Joe's serving size is 33g. Adding 16g of fat, 8g of carbohydrate, and 8g of protein we get 32g. This is much more consistent and the discrepancy is probably due to rounding. If we had 16.3g of fat, 8.4g of carbohydrate, and 8.3g of protein everything would add up properly, but by rounding to whole numbers we would lose 3% precision.
How about the Calories? Fat has 9 Calories per gram, and protein and carbohydrate have 4 Calories per gram. Fiber contributes no calories because it cannot be digested, so we subtract the grams of fiber from the total carbohydrate. The remaining carbohydrates consist of sugars and starches. The Whole Foods seeds have 9×17 + 4×(6-3) + 4×7 = 193 Calories. The Calories from fat are 9×17 = 153. By rounding to the nearest ten, we get 190 total Calories and 150 Calories from fat in perfect agreement with the label.
Trader Joe's seeds have 9×16 + 4×(8-1) + 4×8 = 204 Calories. The Calories from fat are 9×16 = 144. By rounding, we get 200 total Calories and 140 Calories from fat. Oops! Something is inconsistent. The total Calories calculated from the components is 5% larger than stated on the label, and the Calories from fat calculated from the components is 6% lower than on the label.
The % Daily Values are based on a U.S. government recommendation that 30% of the Calories should be from fat, 55% from carbohydrates, and 15% from protein. For a 2000-Calorie diet, this is equivalent to 67g of fat, 300g of carbohydrate that includes 25g of dietary fiber, and 75g of protein per day. The dietary fiber for the Whole Foods seeds should be 3×100/25 = 12% instead of 13%. Trader Joe's Total Fat should be 16×100/67 = 24% instead of 25%, and the dietary fiber value should be 1×100/25 = 4% instead of 5%. These differences are not significant.
Conclusion about Nutrition Facts.
From this analysis we can determine that the Whole Food nutritional label has the wrong serving size. It should probably be 30g or 31g instead of 28g, and therefore, the servings per container should be less than 16 because the weight of the container divided by the serving size should equal the number of servings. We can also conclude that Trader Joe's label has the wrong ratio of components. The most probable discrepancy is that the label has lower amounts of dietary fiber and total fat than it should have, since increasing both of them slightly would make the total Calories and the Calories from fat closer to what is stated on the label, but the protein value listed on the label may also be higher than it should be.The raw sunflower seeds from both stores are probably identical or very similar, but the nutritional information is different through a variety of minor, but annoying errors. Who is responsible for checking these labels?
Ingredients List
Food packages entice consumers with promises of great taste, wholesomeness, and health. Words like "all natural" , "low fat", "diet", "fat free", "nonfat", "sugar-free", and "low calorie" are prominently displayed on many food products. The Nutrition Facts and the Ingredients list which are required by law on packaged foods can be used to determine the veracity of some of these claims.Irradiation Notice
The Radura is an international symbol indicating that a food product has been treated with ionizing radiation. Since 1986, the FDA has required that irradiated foods include labeling with either the statement "treated with radiation" or "treated by irradiation", along with the Radura symbol. In the United States, irradiation labeling requirements apply only to foods sold in stores, and do not apply to restaurant foods or processed foods.In August 2008, The FDA approved irradiation of fresh iceberg lettuce and fresh spinach to try to prevent infections by Salmonella and Escherichia coli O157:H7 (E. coli).[2] In previous years, these types of infections sickened many people in large geographic areas and the embargoes of suspected produce caused great economic losses to retailers and farmers. The FDA considers irradiation an additional tool to reduce the levels of disease-causing microorganisms, but it does not take the place of washing and proper food-handling practices. Consumers should wash fresh and bagged produce before eating unless the packaging specifically states that the product has been prewashed.
FDA Specifications for Health Claims and Descriptive Terms
The FDA provides guidelines about the claims and descriptions that manufacturers may use in food labeling to promote their products[Guidance for Industry: A Food Labeling Guide]:| Claim | Requirements that must be met before using the claim in food labeling |
|---|---|
| Fat-Free | Less than 0.5 grams of fat per serving, with no added fat or oil |
| Low fat | 3 grams or less of fat per serving |
| Less fat | 25% or less fat than the comparison food |
| Saturated Fat Free | Less than 0.5 grams of saturated fat and 0.5 grams of trans-fatty acids per serving |
| Cholesterol-Free | Less than 2 mg cholesterol per serving, and 2 grams or less saturated fat per serving |
| Low Cholesterol | 20 mg or less cholesterol per serving and 2 grams or less saturated fat per serving |
| Reduced Calorie | At least 25% fewer calories per serving than the comparison food |
| Low Calorie | 40 calories or less per serving |
| Extra Lean | Less than 5 grams of fat, 2 grams of saturated fat, and 95 mg of cholesterol per (100 gram) serving of meat, poultry or seafood |
| Lean | Less than 10 grams of fat, 4.5 g of saturated fat, and 95 mg of cholesterol per (100 gram) serving of meat, poultry or seafood |
| Light (fat) | 50% or less of the fat than in the comparison food (ex: 50% less fat than our regular cheese) |
| Light (calories) | 1/3 fewer calories than the comparison food |
| High-Fiber | 5 grams or more fiber per serving |
| Sugar-Free | Less than 0.5 grams of sugar per serving |
| Sodium-Free or Salt-Free |
Less than 5 mg of sodium per serving |
| Low Sodium | 140 mg or less per serving |
| Very Low Sodium | 35 mg or less per serving |
| Healthy | A food low in fat, saturated fat, cholesterol and sodium, and contains at least 10% of the Daily Values for vitamin A, vitamin C, iron, calcium, protein or fiber. |
| "High", "Rich in" or "Excellent Source" | 20% or more of the Daily Value for a given nutrient per serving |
| "Less", "Fewer"
or "Reduced" |
At least 25% less of a given nutrient or calories than the comparison food |
| "Low", "Little", "Few", or "Low Source of" | An amount that would allow frequent consumption of the food without exceeding the Daily Value for the nutrient - but can only make the claim as it applies to all similar foods |
| "Good Source Of", "More", or "Added" | The food provides 10% more of the Daily Value for a given nutrient than the comparison food |
