One reason people gain weight is eating more calories from food than what they need for
energy over 24 hours. Metabolism is the amount of energy a person uses over 24 hours.
Researchers want to study the relationship between changes in metabolism and how much a
To see how much food a person eats when the body's temperature is cooled. To study how
changes in metabolism may alter the amount of food a person eats.
Healthy people ages 18-55.
Participants will stay at NIH for 20 days.
During the first 4 days, participants will have:
- Medical exam
- Blood and urine tests. One blood test includes drinking a sugar solution.
- DXA body composition scan
- Questions about foods they like, physical activity, and personal behavior
- Exercise test on a stationary bicycle
Participants will spend 24-hour periods in a metabolic chamber. The chamber will be at normal
room temperature or cooler.
Some times, participants will eat a diet that matches their daily needs. Other times, they
can eat as much as they wish from a vending machine.
Participants will have blood and urine collected.
Participants will swallow an ingestible wireless sensor and wear a small data recorder
On the second to last day, participants will stay in the metabolic chamber but only consume
water and non-caffeinated sugar-free beverages.
Participants will come back for 1-day visits at six months and one year from the first
admission. They will have blood and urine tests, and a DXA scan. They will answer questions
on physical activity and food habits.