(HealthDay)—Few situations can trip up someone who is watching their weight like an all-you-can-eat buffet.
But a new research letter published in the April issue of the American Journal of Preventive Medicine suggests two strategies that may help dieters survive a smorgasbord: Picking up a smaller plate and circling the buffet before choosing what to eat.
Buffets have two things that raise nutritionists' eyebrows—unlimited portions and tons of choices. Both can crank up the calorie count of a meal.
"Research shows that when faced with a variety of food at one sitting, people tend to eat more. It is the temptation of wanting to try a variety of foods that makes it particularly hard not to overeat at a buffet," says Rachel Begun, a registered dietitian and spokeswoman for the Academy of Nutrition and Dietetics. She was not involved with the new study.
Still, some people don't overeat at buffets, and that made study author Brian Wansink, director of the food and brand lab at Cornell University in Ithaca, N.Y., wonder how they restrain themselves.
"People often say that the only way not to overeat at a buffet is not to go to a buffet," said Wansink, a psychologist who studies the environmental cues linked to overeating. "But there are a ton of people at buffets who are really skinny. We wondered: What is it that skinny people do at buffets that heavy people don't?"
Wansink deployed a team of 30 trained observers who painstakingly collected information about the eating habits of more than 300 people who visited 22 all-you-can-eat Chinese buffet restaurants in six states.
Tucked away in corners where they could watch unobtrusively, the observers checked 103 different things about the way people behaved around the buffet. They logged information about whom diners were with and where they sat—close or far from the buffet, in a table or booth, facing toward or away from the buffet. Observers also noted what kind of utensils diners used—forks or chopsticks—whether they placed a napkin in their laps, and even how many times they chewed a single mouthful of food.
They also were taught to estimate a person's body-mass index, or BMI, on sight. Body-mass index is the ratio of a person's weight to their height, and doctors use it to gauge whether a person is overweight.
The results of the study revealed key differences in how thinner and heavier people approached a buffet.
"Skinny people are more likely to scout out the food. They're more likely to look at the different alternatives before they pounce on something," Wansink said. "Heavy people just tend to pick up a plate and look at each item and say, 'Do I want it? Yes or no.'"
In other words, Wansink said, thin people tend to ask themselves which dishes they most want out of all the choices offered, while heavier people ask themselves whether they want each food, one at a time.
Thin people also were about seven times more likely to pick smaller plates if they were available than those who were heavy.
Those behaviors also appeared to help people eat less. People who scouted the buffet first and used a smaller plate also made fewer trips to the buffet, whatever their weight.
There were other key differences in how thinner and heavier people acted, Wansink said. Thin people sat about 16 feet farther away from the buffet, on average, than bigger people. They also chewed their food a little longer—about 15 chews per mouthful for those who were normal weight compared with 12 chews for those who were overweight.
Those behaviors weren't associated with taking fewer trips to the buffet, but researchers think they may be habits that help thinner people regulate their weight.
"The interesting thing was that almost all of these changes were unconscious to the person making them," Wansink said. "They essentially become habits over time."
A nutrition expert who was not involved in the study praised the research, but questioned whether these strategies might really be powerful enough help.
"As with all of Wansink's observations, these are insightful and useful," said Dr. David Katz, director of the Yale University Prevention Research Center, in New Haven, Conn. "But in some ways, they are like looking for the reasons why some people got wet sooner than others when the Titanic went down. The bigger issue was: The ship was sinking, and everyone was in the same boat."
Katz said the best advice for dieters might be to avoid a buffet's temptations in the first place. "By all means, survey the scene and choose a small plate," he said. "But, better yet, avoid the all-you-can-eat buffet altogether."
Explore further: Mindless eating: Losing weight without thinking
For more on weight loss, head to the American Heart Association.