04 June, 2008

Calculate calories from fat

Calculate Fat Calories.

• Each gram of fat has 9 calories.

• "Fat Free" claims on labels

Food can be labeled "fat free" and listed as having 0 grams of fat if the actual fat content is less than 0.5 grams. This is how foods can have oil or high-fat ingredients listed in their ingredients yet claim to have only 0 grams of fat.

• Hidden fat

The fat we are most familiar with is the triglyceride. All oils
are triglycerides. However, there are also other forms of fat that
you will see in ingredient lists. They are: lecithin, monoglycerides, and diglycerides. These are fats just like triglycerides and also have 9 calories per gram. Mono and
diglycerides are treated by the body in the same way as regular oil(triglycerides). Lecithin metabolism is somewhat different.

• Determining %CFF (percentage of calories from fat)

One useful measure of fat is the percentage of calories as fat. To
find this percentage you need to know both the total calories and grams of fat:

%CFF = 100 * (grams of fat X 9) / (total calories)

Example: A pack of Mushroom Soup is labeled as having (per serving) 2g fat and 60 calories.
Thus, the % calories from fat is

100 * (2 * 9) / 60 = 100 * .30 = 30% calories from fat

• % Fat-free on a food label

When % fat is listed on a food label, this is NOT %CFF as
calculated above. Food labels use fat percentage by weight not
calories. For instance, 1% milk is milk with 1% fat by weight. It
has 23%CFF.

In the previous example, the soup is labeled as
"99% Fat Free! (1% fat as served)". But from our prior
calculations, we showed it has 30%CFF.

• Converting from % fat by weight to %CFF

There is no simple way to convert from a weight percentage to a
calorie percentage. The reason is that the conversion will depend
on how much water, fiber, and other non-caloric ingredients are in
the item. For instance, you could add a drop of oil to a glass of
water. By weight, it would have less than 1% fat, yet 100% of the
calories would be from fat. One can calculate a lower bound on the
%CFF, however. If a product has X% fat by weight, it must be at

%CFF = 900 X / (400 + 5 X)

Keep in mind this is just a lower bound, the true %CFF will probably be much higher. It is better to use the fat formula as shown above.

• Definition of terms used in food labeling

FAT FREE: less than 0.5 grams of fat per serving.
LOW FAT: less than 3 grams of fat per serving.

Hence calculate all your fats with discretion & care.

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