Background:
Diet is one of the most modifiable behaviors affecting health. But diet assessment measures that are based on self-report can be inaccurate. Researchers want better ways to address the role of diet in chronic disease. They want to see if stable isotopes can be used to better assess what people eat.
Objective:
To see if stable isotopes can help scientists identify things people eat.
Eligibility:
Healthy adults ages 18 to 65
Design:
Participants will be screened with a medical history and physical exam. They will have blood and urine tests. These tests will be repeated during the study.
Participants will stay in the inpatient unit of the NIH in Phoenix, Arizona, for 13 weeks.
For 7 days, participants will eat a diet prepared by the NIH kitchen. They will get balanced meals that are 50% carbohydrates, 20% protein, and 30% fat. Then participants will be randomly placed on one of 3 diets containing different percentages of carbohydrates from soda.
Participants height and weight will be measured. The amount of fat and muscle in their body will be measured by body scans that are similar to x-rays.
Participants will have oral glucose tolerance tests. They will consume a sugar drink and then give blood samples over 3 hours.
Participants will give hair and stool samples.
Participants will complete a diet questionnaire. It assesses their food intake over 24 hours.
Participants will complete behavioral questionnaires and computer performance tests.
Participants will have fat biopsies taken from their stomach and thigh.
Participants will have three 24-hour stays in a metabolic chamber. It is used to measure metabolism.
Body mass index less than or equal to 35 kg/m² to minimize the impact of body size on isotope measurements.
Women and men between the ages of 18-65 years will be recruited for this study
Healthy, as determined by medical history, physical examination, and laboratory tests.
Fasting plasma glucose greater than or equal to 126 mg/dL
Alopecia totalis or inability to grow hair (at least one inch of hair required to obtain sample)
Use of medication affecting metabolism and appetite in the last three months
Medically- or self-imposed dietary restrictions that would limit a participant s ability/willingness to consume the diet to which they are randomized