THURSDAY, Nov. 18, 2004 (HealthDayNews) -- By reducing calorie density by 30 percent and reducing serving sizes by about a quarter, Penn State researchers eliminated 800 calories a day from the diets of young women -- and the women didn't even notice the missing calories.
"We lowered the energy density, or calories per gram, of the participants' meals by incorporating more vegetables and fruit in recipes and also using food products reduced in fat and sugar," study director and nutrition expert Dr. Barbara Rolls said in a prepared statement.
"The subjects found the smaller, lower energy density meals just as palatable, filling and satisfying as the big, high-calorie menu items -- and they didn't compensate for lowered intake on the first day by eating more on the second day of the study," Rolls added.
The study included 24 women, aged 19 to 35. On two consecutive days a week, for four weeks, they had breakfast, lunch and dinner at Penn State's Laboratory for the Study of Human Ingestive Behavior. The women also took home specially prepared evening snacks.
The same two-day menu was served over the four weeks, but variations were made in the portion size and caloric density of the menu items. Those variations included the substitution of items with calories reduced by 30 percent, 25 percent reductions in portion size, or both.
A 30 percent reduction in energy density resulted in a 23 percent decrease in daily calorie intake, the researchers report, while a 25 percent decrease in portion size led to a 12 percent reduction in calorie intake.
"This study shows that even small reductions in the energy density or portion size of food are likely to decrease energy intake. The results suggest that home cooks and restaurants could take an easy step toward obesity prevention by adding more fruits and vegetables and trimming the fat to decrease energy density without having to serve tiny portions," Rolls said.
The findings were presented Nov. 15 at the North American Association for the Study of Obesity annual meeting in Las Vegas.
The American Cancer Society shows you how to calculate your daily calorie needs.