Reaching for low-fat snacks could actually make you fat, according to a new study published in the Journal of Marketing Research.
Cornell University researchers found that people consume more calories when they eat low-fat snacks than when they eat the regular versions -- especially if these people are already overweight.
And while information on proper serving sizes seemed to slow down the snacking urges of normal weight people, a companion study found that overweight people ate more low-fat snacks regardless of the serving size on the label.
The study found that people tend to underestimate the amount of calories in low-fat snacks and overestimate how much of these snacks they think they can safely eat.
It's an easy mistake to make. Participants in the study expected the low-fat snacks they ate were 20 to 25 percent lower in calories, so they thought they could eat more.
Like many folks, they mistakenly believed that "low-fat" is equal to "low-calorie."
In reality, the low-fat snacks used in the study were not that much lower in calories than the regular versions -- which is usually the case for other low-fat snacks on supermarket shelves.
True, the low-fat snacks had 59 percent less fat. But they only contained 15 percent fewer calories per serving.
So the low-fat halo -- the illusion that everything low-fat is also healthy -- led overweight participants in the study to load up on these snacks, consuming an average of 90 more calories when a snack had "low-fat" on the label. That was about a 50 percent increase.
Normal weight people in the study also seemed enticed by "low-fat," but they didn't do quite as much damage. They ate 30 more calories per snacking session, on average.
But for both groups, the results show that these seemingly innocent low-fat snacks actually contributed more calories to the diet because more were eaten.
The Devil is in the Labels
The authors of the studies concluded that low-fat labels give people the mental permission to eat more. People appear to feel less guilty about how much they eat when they reach for a low-fat snack, which translates into eating more.
Co-author Brain Wansink calls low-fat labels one of the "hidden persuaders" that get you to overeat -- or to eat more than you intended.
He chronicled his clever studies on human food behavior in the eye-opening and entertaining new book Mindless Eating: Why We Eat More Than We Think (Bantam, 2006).
"If we're looking for an excuse to eat, low-fat labels give it to us," Wansink said.
Low-fat labels are just one of the invisible cues that can make us reach for more. Wansink said that large containers or serving dishes also subconsciously coax us to eat more more calories than we would otherwise eat.
How to Avoid the "Low-Fat" Snack Trap
Here are ways you can make snacks work for you, instead of against you:
Do not let "low-fat" dominate your decisions about snacks. Rather, keep track of calories as well as fat grams.
Build in portion control by buying prepackaged, 100-calorie snacks, or repack your own mini-portions in plastic bags for easy grabbing.
Resist the temptation to eat directly from a package. Always portion food out into a plate or bowl so you see exactly how much you are eating.
Opt for naturally low-fat snacks, such as fresh fruits and vegetables, rather than low-fat, processed snacks like cookies, crackers and chips.
Eat a little protein to help boost the satiety -- the hunger-busting quality -- of your snacks. Good options include string cheese, a handful of almonds or apple slices topped with a dollop of peanut butter.
Keep tempting treats out of sight and out of mind. Stash them in a hard-to-reach cupboard or in the back of the refrigerator.
Replace the cookie jar on your kitchen countertop with a bowl of fresh fruit.
Make snacking a conscious activity. It's easy to lose track of how much you're eating if you're watching TV or surfing the Internet.
Never wolf down your snack over the sink or in front of an open refrigerator. Get out a clean plate and sit down at the table.
Pour yourself a tall glass of water when the urge to snack strikes. You may find that you were really thirsty rather than hungry.
Skip the urge to nibble when you're bored, frustrated or stressed. Instead of reaching into the fridge, walk your dog or call a friend.
Plan your snacks for home, work and when you're on the run. Keep a supply of air-popped popcorn, dried fruit, soy nuts, trail mix, snack-size cereal boxes, instant oatmeal and whole-grain crackers on hand.
Janet Helm is a registered dietitian and nutrition consultant in Chicago.