ISU researchers seek females for study on energy expenditure

AMES, Iowa -- Scientists at Iowa State University are recruiting females for a study that will examine how lean body mass contributes to energy expenditure in women who are of normal weight versus women who are overweight.

The researchers are looking for healthy, premenopausal women, 18 years of age and older, who are non-smokers and are not pregnant or breastfeeding. Participants must have a body mass index (BMI) that is either between 18 and 25, or 30 and above. (An online BMI calculator is at

Women interested in participating in the study will be invited to the research clinic on the Iowa State campus in Ames, where they will complete questionnaires pertaining to their health, nutrition and physical activity. Participants also will be measured for height, weight, blood pressure and body composition. For participating in the screening visit, each woman --whether selected for the study or not -- will receive information about her muscle and fat mass and an analysis of her usual dietary intake.

Eligible women will be asked to make four additional visits to the research clinic during the two-week study period. These visits will involve further assessment of body composition, and measurements of leg strength and energy expenditure. Participants will be asked to record their daily food intake and wear an activity monitor for four days of the study period. Each woman who completes the study will be paid for each of the four visits, and will receive information (in addition to information received at the screening visit) about her muscle, fat and bone mass, physical activity, dietary intake and energy expenditure.

The causes of being overweight and obese are complex and remain unclear, said ISU nutrition professor Paul Flakoll, who is leading the research with doctoral student Darcy Johannsen.

"Obesity is rapidly becoming our most serious global public health threat. In the U.S., a staggering 31 percent of the adult population is obese and another 34 percent is overweight. These conditions are associated with increased risk of developing type 2 diabetes and heart disease," said Flakoll, who is director of the Center for Designing Foods to Improve Nutrition.

"From this study, we hope to determine how lean body mass -- the metabolically active tissue in our body that is responsible for burning calories -- contributes to energy expenditure in women who are of normal weight versus those who are overweight," Flakoll said.

"We want to discover if and how measurements of daily energy expenditure, physical activity, and strength are different in overweight women versus normal-weight women who have similar lean body mass. Understanding the role that lean body mass plays will help us determine how it affects the development of overweight and obesity," he said.

Women who are interested in participating in this study may contact Darcy Johannsen, (515) 294-1216 or