Health Options Alan Titchenal  & Joannie Dobbs                   Wednesday, September 16 , 1998

Don't play percentages regarding fat

The message about excess dietary fat being associated with increased incidence of coronary heart disease, cancer and adult-onset diabetes appears in the news daily. The U.S. Department of Agriculture's Dietary Guidelines indicate that people should eat diets with less than 30 percent of the calories from fat. Since 1965, statistics show that Americans have decreased the fat in their diets from about 45 percent of their total calories to 35 percent.

It looks like we're eating less fat, so you would expect that Americans are getting thinner and fitter. But this is not the case.

More adults and children are overweight or obese than before. At least part of the reason for this weight gain is that we are actually eating more fat.

A recent USDA Center for Nutrition Policy and Promotion Publication (April 1998) docu­ments that while the relative fat consumed (percentage of calories from fat) by Americans is declining, the total amount of fat consumed is increasing. The apparent contradiction results from using percent calories from fat as a measuring tool rather than grams of fat. The problem is that total calorie intake has increased. To use an analogy – 35 percent of a large pie is greater than 45 percent of a small pie.

Focusing on percent of calories from fat can be very misleading and can lead to overeating of both calories and total dietary fat.

Foods contain four components that contain energy – usually expressed as calories. The components are: carbohydrate, protein, fat and alcohol. Expressing the amount of any of these food components as a percentage obviously will be affected by what other food components are part of the food.

Using the following examples, which food do you think contains the least calories?

Example 1: A plate of Alfredo pasta containing 21 percent calories from fat or a plate of capellini verde containing 45 percent calories from fat.

Both dishes contain 15 grams of fat, but the Alfredo contains 330 calories more than the capellini because it has more carbohydrates.

Example 2: A dessert bowl of mango pudding at 27 percent calories from fat or a bowl of mango tapioca at 31 percent of the calories from fat.

Even though the two dishes have similar percentages, the mango pudding has nearly twice the fat and three times the calories as the tapioca.

These two examples show that the greater the carbohydrate, protein, or alcohol content in a recipe, the smaller the percentage of calories from fat will appear.

Here are the “facts” about our eating patterns based on real food and real quantities:

The actual pounds of fat consumed per person per year in the last 20 years has risen 15 pounds. Cooking oils and shortening in­creased the most, while butter, margarine and lard remained the same. That is equivalent to an additional 170 calories consumed per day per person.

Sugar consumption has increased by 30 pounds annually (about 150 calories per day) and flour consumption has increased by 20 pounds (100 calories per day) over the same period.

All in all, we are eating more than 400 calories a day more than we did 20 years ago. And that translates into a lot of added weight each year.

Because American consumption of sugar and flour has increased more than fat consumption, the percent of calories from fat have declined even though the amount (grams) of fat increased.

The moral of the story is to make sure that you don't get fooled by the way fat and calorie information is expressed.