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
Too-Much Traps
As if knowing a reasonable serving size weren't hard enough, external factors also trigger overeating. Where you are, what you're doing, and who you're with all affect how many calories you're likely to consume. When you're in a restaurant with low lighting, you tend to eat more. You also eat incrementally more as the number of people at the dining table increases, and you'll eat more if you're watching television or reading the newspaper. According to Wansink, eating in front of the TV can increase your consumption as much as 60 percent, depending on how long you sit there watching.
The size of the plates we eat from, the bowls we serve from, and the utensils we use can also make us eat more than we mean to. Wansink has found that when we serve ourselves from bigger bowls and use larger serving spoons, we scoop up at least 25 percent more. Yet when we make the simple switch to eating off of smaller plates--making the amount we put on them look larger--we automatically eat at least 25 percent less.
But you don't have to eat on a mini plate all by yourself in a brightly lit spot with no television or reading material to eat sensibly. Just being aware of these factors can help you consume less. Something as simple as using large bowls for low-cal foods like salad and small bowls for ice cream can make the difference between losing and gaining a few pounds.
Know Your Magic Number
Once you've mastered portion sizes and shutting out external eating cues, your work isn't done. Most of us still don't have a clue about how many calories we should be eating every day, a number that is influenced by age, gender, height, weight, and activity level (for a simple calculator, try dietdetective.com). Once you determine that you should be eating, say, about 2,200 calories a day, you can divide that throughout the day to figure out about how much you should be eating at each meal. "Get a rough idea of your calorie needs that you can use as a starting point, and then adjust up or down depending on your weight goals," says Rolls. With your calorie budget in hand, you can keep a food-and-exercise diary to document how much you really eat and burn on a daily basis (see "Eat, Exercise, Take Notes,") so that you can compare it to your actual calorie needs.
As most people find when they start keeping a food diary, it's not the occasional slice of death-by-chocolate cake that does us in. It's what Wansink calls the "mindless margin"--approximately 100 calories extra each day that we take in through larger portions or incidental snacking that make the difference between gaining or losing a few pounds over a year. Of course, if we continue eating these mindless calories over several years, they can add up to significant weight gain. But the good news is that losing those two or three last pounds in a year requires cutting only about 25 calories from your diet each day or burning 25 extra during your daily workouts.
The Exercise Exception
While running is one of the most effective activities for burning calories, it's still a lot easier to eat--or not eat--25 calories (a Hershey's Kiss) than it is to run them off (at least a quarter mile). And that's why runners who spend months training for a marathon might still be carrying a few extra pounds as they cross the finish line. "There's also a big variable in the energy cost of running--which differs between genders, ethnicities, age, weight--which can result in 10 to 15 percent variances in how much weight two different runners might lose," says Ralph La Forge, M.Sc., a physiologist at Duke University. If you've always relied on the notion that 35 miles of running will burn exactly 3,500 calories and, therefore, result in the loss of one pound of body weight, you're missing out on an important part of the equation.
As La Forge explains, that 100-calories-per-mile standard (which is built into the readouts on your gym's treadmills) is the gross energy cost of running--strictly how many calories you burn going from point A to point B. But runners who are trying to lose weight need to also know the net energy cost of their runs so that they can more accurately calculate their entire calorie burn for the day. For example, if you go for a three-mile run and it takes a half hour, you need to subtract out however many calories you would have burned during those 30 minutes even if you'd been just sitting at your desk (about 80 calories). That means the true net energy cost of your run over the course of the day is more like 220 calories than 300.
It's also important for weight-conscious runners to factor in what La Forge calls "energy conservation." "About a third of us wipe out almost half of the energy expenditure of a workout by conserving energy afterward," he says. If your long run leaves you so exhausted that you spend the rest of your Saturday on the couch watching movies rather than cleaning the house or working in the garden, you may end up burning fewer calories throughout the day than if you did a slightly shorter run but still had the energy to take the kids to the park in the afternoon for batting practice. And, of course, you have to beware of "energy compensation"--better known as eating more calories after a workout than you burned off during the run. "I met a guy who ran purely because he liked ice cream," says Wansink. "But to equal his daily pint, he needed to run 12 miles every day." Most of us don't (or can't) do that.
"If you're exercising primarily for health, none of this matters that much," says La Forge, who takes note of the many benefits of exercise, including its link to a reduced risk of chronic diseases such as diabetes and heart disease. But if you're running to lose weight, you have to keep in mind all the variables. "I believe in exercise," says Wansink. "But I also know how quickly you can eat many more calories than you will run off in a normal workout."
