People who struggle with weight loss may be missing some key ingredients in their diets that can help them shed pounds. Penn State researchers have shown that there is actually a way to eat the same amount of food you normally do and still lose weight.

The trick is to eat foods that have a low fat content, but most importantly contain a lot of water. In effect, this makes a person feel full while cutting back on calories.

"Most people take in calories without even noticing," said Barbara Rolls, professor of nutritional sciences and Guthrie Chair of Nutrition.

Marc Kordell (freshman-aerospace engineering) said he doesn't pay attention to his calorie consumption.

Rolls provides guidelines for healthy eating in Volumetrics, a book she co-authored with researcher Robert Barnett and suggests foods with a high water content, such as salad, soup, fruits, vegetables and low-fat smoothies as replacements for high-calorie foods. Her main point is to use the water in foods to dilute calories and fill the stomach. However, simply drinking a large amount of water does not accomplish these goals nor provide nutrients.

The guidelines put forth in her book are quite practical, she said, since readers are advised to eat many types of foods, unlike the Atkins Diet that glorifies high-protein foods. Besides eating water-rich foods, Rolls suggests eating reduced-fat foods so people can discover, "how low they can go without making the foods unacceptable."

Fat should also be reduced in a diet because each gram of fat provides nine calories as opposed to protein and carbohydrates, which provide four calories per gram.

Some people may think that when you cut the fat, the flavor of food is sacrificed. Danielle Donnelly (freshman-advertising) said she tries reduced-fat foods only if they look good.

But Rolls said, "When you reduce the fat most people don't even notice."

And even though she advocates fat reduction, she does not advise cutting fat completely.

Not having any fat in your diet is unrealistic, said Diane Mitchell, coordinator of the Penn State Diet Assessment Center. "Plant sources of fat also provide essential fatty acids which are necessary for good health."

The big reason why dieters fail to lose weight is they starve themselves and deprive themselves of energy, said Rolls. One way this unhealthy cycle of dieting can be avoided is to change the foods a person eats, not just the portion size. As a result, a person can slim down and feel full by eating a large amount of water-rich, low-fat foods instead of the same amount of high-fat, high-calorie foods, said assistant professor of nutritional sciences Carla Miller.

What is striking and may concern college students at all-you-can-eat campus dining halls is the finding that people adjust their hunger levels with the availability of food. In turn, people feel hungrier and will eat more food if it is close at hand, consuming more calories than necessary for physical activity, Rolls said.

Some students' eyes are bigger than their stomachs.

Ashley Andrews (freshman-liberal arts), who thinks dining hall food is tempting, said, " I usually get a lot of stuff but only eat a little bit of everything."

Donnelly agreed, saying, "I always put so much food on my plate and don't eat it all."