Americans get confused when they try to understand the food labels ("Nutrition Facts") on their packaged food. This is partly because the Food and Drug Administration and the Department of Agriculture often seem more interested in the welfare of the food industry than in the health of consumers.
For example, even though health practitioners and the federal government itself tell consumers to watch their salt intake, processors continue to add salt to packaged food. Salt occurs naturally in many foods, so why do processors add more? Perhaps processors think that extra salty food will make the consumers thirsty enough to buy more soda and other beverages that the processors also make.
"Serving Size" is supposed to be the amount an average adult would eat at one sitting as part of a regular meal. However, a 6-ounce container may have anywhere from 1 to 3 servings, depending on the food inside the container. A 6-ounce can of Crabmeat contains one serving, while a 6-ounce can of Pink Salmon Chunks contains 3 servings.
With the federal government's approval, processors use labeling that helps to sell the product, regardless of how confusing or deceptive the label is to the consumer. If a consumer sees "200 calories" on a can of tuna fish, he might not buy it because 200 is a lot of calories. But if the consumer sees "20 calories" (because the can of tuna fish has 10 servings!), he doesn't worry that the can contains too many calories. All he sees is the number 20. That makes him happy, and it makes the processor happy.