Focus
on Research Focus
on Research 
By Barbara Hale
Public Information
Being able to enjoy your favorite foods, feel full after meals -- and still lose weight -- sounds like having your cake and eating it too.
But "feeling full on fewer calories" is exactly what is promised by a new approach to eating based on research conducted by Barbara Rolls, who holds Penn State's Guthrie Chair of Nutrition in the College of Health and Human Development.
The eating plan is detailed in a new book, Volumetrics: Feel Full on Fewer Calories, to be published this month by HarperCollins. The authors are Rolls and nutrition writer Robert A. Barnett.
The basic strategy of "volumetrics" -- eat a satisfying volume of food while controlling calories and meeting nutrient requirements -- is based on a series of studies conducted by Rolls in Penn State's Laboratory for the Study of Human Ingestive Behavior over the last seven years.
These studies show that eating your usual amount but selecting low-energy density meals, which have fewer calories per ounce and contain lots of fruits and vegetables, offers a way to cut back on calories and still leave the table feeling full and satisfied.
"When we first started these studies, we thought that fat played an important role in satiety," Rolls said. "We found that, when you keep the calories and volume of food that a person eats fairly constant, you don't see any special effects for fat in terms of reducing hunger."
The Rolls research team also investigated the effects of drinking water before or during meals. The results showed that the energy density of food mattered most in producing satiety, the feeling of leaving the table well-satisfied.
Rolls said her group's research has shown that feeling full depends on eating a satisfying amount of food. Tiny portions just don't do it. The energy density of food, or the ratio of calories to the weight of food, is what matters most in order to feel full while controlling calories. Foods with a high energy density have lots of calories in a small serving and are typically lower in water content. For example, a 100-calorie serving of raisins, a high-energy density food, is only one-quarter cup. A 100-calorie serving of grapes, a food low in energy density and high in water content, is one and two thirds cups.
In one study, women who had a low energy density soup as a first course ate fewer calories overall during lunch. However, soup is not the only water-rich food that can help decrease calorie intake, said Rolls. She said her group's research has shown that by consuming other water-rich foods, dieters don't have to limit portion size to less than they normally consume.
Following usual eating habits but modifying recipes to reduce the energy density is a good way to apply these research findings at home, Rolls said.
For example the energy density of chili can be reduced by adding leaner meat, celery, extra tomatoes and mushrooms to increase bulk but not calorie content.
"People on diets often substitute pretzels for high-fat, high-calorie snacks. But pretzels have a low-water content and don't fill you up, so you eat more of them. A snack with higher water and fiber content, for example, an apple, would be a better choice," said Rolls.
Rolls' new book provides more information about the energy density of specific foods along with menus, recipes, and tips for modifying favorite dishes. A food guide contains a list of more than 600 foods divided into four categories to help readers select a satisfying, lower-calorie diet.
This month, more than 100 of Africa's greatest writers and artists, more than 300 African and international scholars and researchers, as well as publishers, students, children and business and political leaders from throughout Africa and the world, will gather in Asmara, Eritrea, for an international conference, "Against All Odds: African Languages and Literatures into the 21st Century."
Participants will take part in a week of discussions, translation and publishing workshops, plays, concerts, dance performances and art exhibitions all centered on the hopeful future of African languages and literatures.
Charles Cantalupo, professor of English at Penn State Schuylkill, who conceived the idea for this project, serves as one of the conference organizers. Penn State, Africa World Press Inc. and the Red Sea Press Inc. are sponsoring the conference, along with a long list of others.
According to Cantalupo, the realities of brutal colonialism and corrupt neocolonialism, poverty and starvation, AIDS and other pandemics, and racial and ethnic wars have been a common context for African artistic achievement in the 20th century.
"African writers, and especially African women writers, have worked with circumstances stacked against them, but in the context of political and economic challenges and social persecution, they have made tremendous achievements, against all odds," he said.
"The conference is an opportunity to emphasize the fruits of peace -- including a renewed interest in African languages and a renaissance of accomplishments in cultural and artistic production," he said.
For more information about the conference, visit the Web at http://allodds.outreach.psu.edu/.
A gene for a protein that fuels lung-cancer growth is more active in women than in men, according to a report by a University
of Pittsburgh-led research team. Principal investigator on the study is Sharon Shriver, who is now an instructor of biology at the University Park campus.
The team also discovered that nicotine found in cigarettes induces gene activity. Their report offers the first biological explanation for the greatly increased risk women face versus men in developing lung cancer. If substantiated in future studies, this research could provide a valuable marker for predicting which women are most likely to develop the disease or detecting dangerous precancerous changes.
The research team found an increase in the expression of the gene for gastrin-releasing peptide receptor (GRPR), which is found on the surface of cells lining the lung. When stimulated by its hormone, gastrin-releasing peptide, GRPR triggers cell proliferation typically seen in lung cancer. The team also discovered that nicotine found in cigarettes stimulates expression of the GRPR gene in lung cells.
"Our research strongly suggests that women are likely to develop lung cancer after much less smoking exposure than men and much earlier in life, regardless of their smoking history. The take-home message, especially for teen-age girls, is that they should stop smoking -- or better yet, never start," said Shriver.
The difference between the sexes may be related to the location of the GRPR gene on the X chromosome. Women have two X chromosomes, whereas men have one.
For more information, check the Web at http://www.bio.psu.edu/People/Faculty/Shriver/ or http://www.nci.nih.gov/