Want to eat a healthier breakfast? Psychologist Brian Wansink, PhD, might tell you to make a simple change: Move your bran cereal to the front of your pantry and put the Pop Tarts in back.

Wansink, director of the food and brand lab at Cornell University and author of the 2006 book "Mindless Eating: Why We Eat More Than We Think," studies how things like plate size, menu descriptions and food placement affect what we eat—and how much. He's found that people are much more likely to eat the most conveniently placed food item in their pantry. He's also found that eating from a bigger bowl or plate, or drinking from a wider glass, can make people consume as much as 30 percent more calories—which, over a lifetime, could add up to dozens of extra pounds.

Wansink, who has been called the "Sherlock Holmes of food," solves his mysteries in a lab that he can dress up to look like a dining room, a restaurant, an airplane or anywhere else that people eat. His creative experiments are showing that some things that many people take for granted—such as the idea that our body knows when it's full—are simply false.

In one of his best-known studies, published in 2005 in the journal Obesity Research (Vol. 13, No. 1), he and his colleagues lured participants into their restaurant-lab with the offer of a free lunch. Half of the participants got a normal bowl of tomato soup. The other half sat down to a meal that seemingly never ran out. Their bowls were linked via a hidden tube to a six-quart vat of soup under the table. As the participants ate, the bowls subtly refilled. So from the participants' perspective, it looked as though they had hardly eaten anything at all.

Wansink and his colleagues let all of the participants eat for 20 minutes, then measured how much soup they had consumed and asked them how full they felt. They found that the participants with the self-refilling bowls ate 73 percent more than those with the normal bowls—but didn't report feeling any more full.

"Your tummy is a really terrible gauge of how full you are," Wansink told a packed house at APA's 2011 Annual Convention, where he described the soup-bowl study and other highlights from his more than a decade of food research.

For example, your stomach is not the only thing that can be easily tricked, he's found. Your tongue isn't very good at figuring out how much you like a food either. Wansink has found, for example, that changing the description of food on a menu—from, say, "seafood filet" to "succulent Italian seafood filet"—can make people rate a particular food as tasting better.

In one study, he and his colleagues served participants dinner, accompanied by a glass of "two-buck Chuck" Trader Joe's wine. They told half the participants that the wine was a new California label. The other half of the participants were told they were drinking North Dakota wine. Not only did the participants who thought they were drinking a California wine rate the wine as tasting better, they actually rated the food as tasting better as well, and the chef as having more training.

It might seem depressing to learn that we are so out of tune with our own tastes, and that we can't rely on our stomachs to know when we're sated. But the good news is that once we understand our hard-wired eating behavior, we can change our environments in ways that make us eat better, Wansink said.

For example, buying smaller plates and glasses.

After he did the study that showed that bigger plates and glasses make people consume more, he said, "I'm pretty sure everyone in the lab went out and bought new ones."

Now, Wansink is aiming to bring his research to one of the front lines in the fight against obesity: school lunch rooms. Through a project he's begun called the smarter lunchroom initiative, he's working with school systems around the country to make simple tweaks that will encourage students to eat more fruits and vegetables and fewer desserts.

In one school cafeteria, for example, he found that food servers dumped fruits into an unattractive metal bin near the steam tables. He bought a cheap fruit basket and piled the fruit artistically inside, and brought in a desk lamp to light up the display. Fruit sales more than doubled.

In another school cafeteria, he moved the salad bar from an isolated spot to a prime location next to the cash registers. Salad bar sales went up more than 200 percent.

Such simple solutions could be an effective and cheap tool to change students' eating habits, Wansink believes. Now, he and his colleagues are thinking big: They've recently received a $1 million federal grant to bring their ideas from the lab to the school system, and they're hoping to have as many as 35,000 schools on board by 2015.