With a basic knowledge of mathematics you can calculate the percentage of calories from fat in a food product, though not the percentages of saturated and unsaturated fats. This is how to do it:

Calories come from three sources: fat, carbohydrates and protein. Fats are frequently called "calorie dense" because they contain nine calories per gram. Carbohydrates and protein contain only four calories per gram.

So, to find the percentage of calories that come from fat in a product, you will need to know the amount of fat and number of calories per serving. If the product has nutrition labeling, both will appear on the package. The percentage will, of course, be the same for any amount of the product.

Let's take a product, Hellmann's Mayonnaise:

The label indicates there are 11 grams of fat and 100 calories per serving, in this case a tablespoon.

First, multiply the number of grams of fat (11) by the number of calories per gram (9) and the total number of fat calories in a serving is 99.

Then, divide the number of fat calories (99) by the number of total calories (100), and multiply by 100. The answer: the percentage of calories that come from fat is 99. (Hellmann's, by the way, lists percentage of fat calories on the label.)

Find the percentage of calories that come from fat in the following products:

(1) Birds Eye Japanese Style Vegetables, 6 grams fat, 100 calories per serving.

(2) Hostess Old Fashioned Donuts, 10 grams fat, 170 calories per serving.

(3) Nabisco Graham Crackers, 3 grams fat, 120 calories per serving.

(4) Giant Lowfat Cottage Cheese, 1 gram fat, 90 calories per serving.

(5) Cremora Non-Dairy Creamer, 1 gram fat, 12 calories per serving.

(The answers appear at the bottom left of this page.

The Answers: (1) 54 percent (2) 53 percent (3) 23 percent (4) 10 percent (5) 75 percent