In the 1950s an average meal of a cheeseburger, French fries and soda pop would be about 600 calories, slightly under one third of the total calories an average person needs in one day.

If you eat that same meal today, you're likely to consume more than 1,200 calories in one sitting — over half of your daily needs. Why such a significant calorie difference for the same meal? The answer: portion distortion.

Portion distortion

Compare the difference in serving size (and calories) of some food and drinks 20 years ago versus today:

Without a doubt, larger food and drink portions significantly affect our eating habits. While common sense may tell you that you simply eat until you feel "full" regardless of how much or little you are served, in fact research studies show that when people are given more food, they tend to eat more of it, even past the point of feeling full.

Studies have shown that people who ate a meal that filled up a small plate reported feeling more "full" compared to those who ate the exact same meal on a large plate (it looked like less food).

Of course, satiety (the sense of feeling full) also depends on the food itself. In general, foods that are high in fiber (like whole grains, fresh vegetables and fruits) increase satiety. Also, because it takes your body longer to digest and absorb protein and fat compared to refined carbohydrates (white bread, white rice), high-protein and high-fat foods keep you feeling full.

We also recommend taking breaks while eating to allow your brain to catch up with your stomach's signals.

Proper portions

In order to provide a frame of reference for food portions, standard serving sizes have been developed by the USDA as part of their Dietary Guidelines for Americans.

To help you understand what a proper portion looks like, it's helpful to associate portions with common objects:

3 ounces = 1 deck of cards or the palm of your hand
1 cup = 1 tennis ball
1 ounce or 2 tablespoons = 1 golf ball

Make a point of reviewing the Guidelines to learn how to create a healthier lifestyle for yourself and your family.

Note: This information is not intended to take the place of advice from a health professional. Check with your physician before starting any diet or exercise program. While all efforts have been made to ensure the information included in this material is correct, new research is released frequently and may invalidate certain pieces of data. 3/07.