SIZE MATTERS
How much are you really eating? Probably more than you think. Here's how to judge for yourself.
By Sally Wadyka
Photographs by Mark Hooper
PUBLISHED 03/04/2007
Runners thrive on numbers--distance covered, time clocked, pace per mile And we're usually pretty good at calculating those accurately. But one area where most runners could use a little help with math is in figuring out how many calories we eat and how many we burn during our workouts. In fact, those five extra pounds that many runners drag around are proof-positive that many of us have trouble with simple addition and subtraction. We typically think we're eating fewer and burning more calories than we really are.
"In general, people will underestimate the calories in a typical meal by about 20 percent," says Brian Wansink, Ph.D., director of the Cornell Food and Brand Lab at Cornell University and author of *Mindless Eating* (Bantam Books, 2006). "But after a tough workout, you might underestimate how much you're eating by as much as 50 percent." His research group studied people training for a marathon and monitored them as they carbo-loaded in the lead-up to race day. The researchers found that on average the runners would guess that they had 1,500 calories on their plates when they actually had about 3,500 calories.
An extra 2,000 calories? That's almost a day's worth of food. Why are we so far off the mark? Turns out there are several factors, including our inability to accurately size up portions, external cues that cause us to overeat, and difficulties gauging our daily calorie budget. And any one of these factors--or some combination of them--can be enough to thwart our best efforts to drop extra pounds or maintain a goal weight. That said, losing a few pounds isn't rocket science. You simply need to take in fewer calories than you burn on most days of the week. With a few key strategies, you can accurately tally the number of calories you eat and burn daily. Learning how to size up your plate and your workouts will help you downsize your waistline.
Portion Distortion
The biggest weight-loss challenge is knowing exactly how much you're eating. It isn't easy. Restaurants typically dish out double and triple servings per entr? and food manufacturers sell megapackages of snack foods at discount prices, so it's difficult to determine a healthy portion of any food. And that's a big problem, since research has proven that we almost always eat nearly all of whatever is on our plates. A 2005 study published in the Journal of the American Medical Association found that people eat an average of 92 percent of any food they serve themselves.
"Part of the problem is labeling, because packages don't tell us in a systematic way how many calories there are per portion," says Barbara Rolls, Ph.D., professor of nutritional sciences at Penn State University and author of The Volumetrics Eating Plan (Harper Collins, 2005). "What is labeled as a serving size varies randomly even in the same category of food." For example, a serving of Chips Ahoy chocolate-chip cookies is three cookies, while for Fig Newtons, it's just two. Serving sizes also don't take into account the calorie density of a food. Other countries provide information on nutritional labels that tells how many calories are in 100 grams of the product, which makes it very easy to compare one food with another. "If you see how many calories are in 100 grams of two different types of potato chips, you immediately know which chip is more caloric," says Rolls.
Numerous studies have confirmed this calorie confusion. Wansink and his colleagues have tested various theories about portions and serving sizes, and the results all point to the fact that we tend to equate the size of the bag or box a food comes in with how much of it we should eat. "Six 100-calorie servings in separate bags is six servings," says Wansink. "Empty them all out into one big 600-calorie bowl, and one serving is now however much we want to eat." The bigger the meal we're eating, the harder time we have estimating its calories (remember those carbo-loading marathoners piling 3,500 calories on their plates). "We get more optimistic about the number of calories we think we're eating as the meals get larger," says Wansink.
