For many people who wish to lose a few pounds, there may be an easier way than counting calories and eating next to nothing. The trick: eating foods with less density.

In several studies led by Penn State Nutritional Science Professor Barbara Rolls, participants who consumed foods with less density, such as fruits, vegetables and soup, had significant weight loss, said Katie Leahy, Rolls' graduate student, who helped with the studies.

In one study, two groups were instructed about healthier diets, but one group was told to increase the amount of fruits and vegetables
they consumed on a daily basis. Researchers found that after the course of one year, the group that consumed more fruits and vegetables saw a significantly greater weight loss than the group that did not change its eating habits, Leahy said.

"A lot of the time, it's reducing the amount of fat in a food or increasing the amount of vegetables or other water rich foods," she said.

Many foods that are less dense and fill you up more are water-based, she said.

In another study, the researchers reduced the energy density and portion size of all foods given over the course of two days for breakfast, lunch, dinner and an evening snack. There was a 25 percent reduction in energy with the decreasing portion size, a 10 percent decrease in intake with decreasing energy density and a 24 percent decrease in energy intake, which shows this is an effective method of weight loss, said Leahy.

"In a lot of studies, we reduce the energy density foods by adding water content," she said.

A good way for students to incorporate less-dense foods into their diet is by eating more broth-based soups, as opposed to cream-based, and eating the soup before a meal to decrease intake at lunch or dinner, Leahy said. Also, adding lots of vegetables to meals such as salad, sandwiches or pasta can help decrease intake by making the stomach feel fuller faster, she said.

"This seems to definitely be helping people lose weight and retrain eating habits. By decreasing volume, you're going to lose weight and keep it off," said Christine Gerbstadt, national spokeswoman for the American Dietetic Association in Altoona. She said she is working on a follow-up study at Drexel University to see what social factors, such as age, sex or income, have to do with the success of weight loss in people who lost 10 percent of body weight in three months.

"It's about changing your perspective; if you have the choice of two tablespoons of raisins or a cup of grapes, the water in the grapes is going to fill you up and keep you more satisfied," Gerbstadt said.

To figure out the energy density, just look at the label and divide the calories by the gram weight, Leahy said.

"For example, take a box of Teddy Grahams. They have 130 calories per 30 grams, so the energy density would be a four," she said.

"This is pretty high, as most fruits and vegetables are under one," she added.

Other high-density foods consists of foods that do not have high water content such as pretzels, peanut butter, cookies and cream cheese, Leahy said.