Use of Stable Carbon And Nitrogen Isotopes to Improve Dietary Assessment for Cardiovascular Disease

This is a controlled feeding study in which the relative validity of stable carbon and nitrogen isotope ratio analysis as a biomarker of dietary intake is compared to controlled feedings and multiple 24-hour recalls. Participants will be randomly assigned to a sequence of diets to be fed on four occasions. Participants will undergo 24 hours of controlled feeding on four non-consecutive days over a month-long period. On the day after feeding, participants will complete 24-hour dietary recalls, and provide blood, hair, and fingernail samples for isotope ratio analyses. The investigators will use a crossover design and the diets will be either high or low in C4 plants (i.e., corn and cane products). A 24-hour urine collection will be done at home during each 24-hour feeding period. Participants will have height and weight measured at the screening visit. Weight will also be measured at each study visit. Additionally, data will be collected via questionnaires administered at each study visit.