Sep 25, 2006

Portion Control: A Tool for Good Health

Amy Campbell

Last week, I wrote about the difference between a serving size and a portion size. As a quick reminder, a portion size is the amount of food that you choose to eat, whereas a serving size is a recommended amount of food to eat. No doubt you’ve caught on that portion sizes of food and beverages continue to grow. Sizes of sodas, French fries, and even dinner plates are bigger than ever before, and as portions get larger, so do people. Surprisingly, though, many Americans have lost sight of portion size.

For a long while, following a low-fat diet was the message to people who wanted to lose weight. The message was, "As long as you don't eat more than X amount of fat grams a day, you can eat what you want and still lose weight." I admit that, as a dietitian, I too got caught up in the "fat-free" craze and would advise my patients that it was OK to eat a little more of something that was fat-free. Fat became more important than calories.

Recently, the American Institute for Cancer Research surveyed people and found that 62% of the respondents believed that it was the type of food they ate that mattered in terms of weight control, rather than the amount of food. And around 50% said that portions served in restaurants have stayed the same or gotten smaller in their lifetimes. However, Americans' average daily calorie intake has risen from about 1800 to 2000 over the past 20 years, and restaurants have switched from 10-inch plates to 12-inch plates. Clearly, portion sizes are on the rise.

Despite all the different weight-loss diets out there, the bottom line is that the amount of food you eat is really the key determinant of your weight. That's not to say that other factors don't play a role in weight control, because they do. But, rather than spending time agonizing over whether to follow a high-carb or low-carb meal plan, or whether you really should eat for your blood type or just become a fruitarian, spend some time first and foremost figuring out how much you really eat. Once you do that, you can make changes. And remember that, as portion sizes increase, your blood glucose levels can increase, too.

This summer, a study out of Cornell University, published in the American Journal of Preventive Medicine, showed that the size of bowls and serving utensils influenced how much people ate. In this study, 85 food and nutrition experts were invited to an ice cream party. Each guest received either a 17-ounce or a 34-ounce bowl and a 2- or 3-ounce serving scoop. Those who had the larger bowls took 31% more than those with the smaller bowls, and those who used the larger scoops took about 15% more than those using the smaller scoops. So, even though these were food experts who undoubtedly had a full understanding of fat, calories, and portion size, they ended up automatically taking more ice cream due to the size of the bowl and the serving scoop.

Other studies show similar results. In a study published in The American Journal of Clinical Nutrition in 2002, scientists at Pennsylvania State University found that, as portion sizes of foods became larger, calorie intake became larger too.

The National Institutes of Health has put together a great slide show called Portion Distortion, which compares portions of commonly eaten foods, such as a muffin, a bagel, and soda, with portions from 20 years ago. To view the slide show, click here and choose Portion Distortion I or II for an eye-opening view of how sizes really have increased.

Next week, we'll go over some tips that can help you keep portion sizes under control.

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