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The purpose of this study is to determine how the variations in a particular gene (APOA2), which either may put individuals at risk for, or protect them from developing obesity in the presence of certain fats in foods, affect gut bacteria and biomarkers relevant to heart disease. Participants will be asked to consume meals provided by the Center for about 14 days, and have blood and stool samples collected 6 times during the study.

Target Population
Men and women ages 18 years and older

Major Exclusions
BMI <27 or >34 kg/m2
Vegetarians or vegans
Pregnancy or breastfeeding
Smoking tobacco products, marijuana (incl. consumption of edibles) or use of nicotine replacement products in the last 6 months
Irregular bowel movements (<3 times per week)
Diabetes or diabetes medications
Kidney, liver, heart, gallbladder or gastrointestinal diseases
Alcohol consumption of 2 or more drinks per day

Length of Study
Approximately 6 weeks

Number of visits
2 screening visits; 6 study visits for collection of saliva, blood and stool samples, as well as collecting dietary and clinical information (i.e., blood pressure, weight, etc.), filling out questionnaires and to pick up prepackaged meals.


Study diet
All foods and beverages will be provided during each diet phase (about 7 days for each phase). The study meals will contain meats, eggs and dairy products for the meat-based diet phase, or will contain only fruits, vegetables, breads, grains, pastas, rice, nuts and spices for the plant-based diet phase.

$40 for screening visits ($15 for 1st screening visit, $25 for 2nd screening visit), and up to $500 for participants who qualify and complete the entire study.

Can I work?
Yes; However, if you are an employee of Tufts University you cannot take sick, vacation or personal days off from work to complete this study.

Length of study

Total length of the study including resident stays and nonresident visits.
This does not mean you will be testing the entire time.

The length of time volunteers are required to stay overnight at the HNRCA. Residents have their own private room, bathroom, television, VCR, and phone during their stay.

The amount of reimbursement for travel and inconvenience.
Number of visits

Total number of nonresident visits.
Study diet

Indicates meals which will be provided by the HNRCA
Can I work?

Indicates if you will be able to work and if so, when.

For more information about this study, please call Volunteer Services at 1-800-738-7555 .

We appreciate your interest in our program and we hope to work with you in the future.

Thank you,
The Recruitment Office
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University