Why is this study being done?
This research is being done to study how eating dinner at different times affects your health. The timing of meals may be important for weight control and heart health. Eating later in the day is linked with risks of obesity and cardiovascular disease, but doctors do not understand why late eating might lead to these problems. Previous studies have not considered the differences in a individual’s internal clock when researching the effects of dinner time on metabolism.
We hypothesize that eating dinner an hour after your biological night, close to bed time will cause problems such as higher fat and sugar levels in the blood during sleep. In this study, we will see what happens to your metabolism when you have dinner 3 hours prior to versus 1 after after your biological night. We will also test if delaying bedtime for several hours, to give your body time to digest, will help your night time metabolism.
How many people will be in this study?
We are looking for 20 healthy volunteers to complete this study.
Where do I go for the study?
This study is at the Johns Hopkins Bayview campus. On your first visit, you will go to the Johns Hopkins Asthma and Allergy Center (JHAAC), 4th floor to meet with our study team. On the study visit, you will go to the Clinical Research Unit. The JHAAC is located at 5501 Hopkins Bayview Circle, Baltimore MD 21224. The Clinical research unit (CRU) is at 4940 Eastern Avenue, 301 Building, Baltimore, MD 21224.
How long do I have to stay in the research unit and what can I do there?
For your your first visit at the research unit, you will check in at 3:00 PM and leave 2 hours after you typically fall asleep. If you are too tired to leave, you are welcome to spend the night. You will stay in your private room for the full visit giving saliva samples every 30 minutes. This room has access to a rest room and TV. During this visit you can use your cellphone with the light on the lowest setting. No laptops are allowed. Snacks can be provided.
For your 3 overnight visits you will check in on 8:00 PM on day 1, and leave at noon on day 3, which is a total time of about 40 hours in the research unit. While you are in the unit, you can do work, walk, and watch TV. You will have a private room and access to a lounge area.
No caffeine or alcohol use is allowed 24 hours before and during all of these visits.
What kind of food will I be served?
Our research nutrition team prepares tasty meals that reflect a typical Western diet, including vegetarian and vegan options. Your eating and sleeping times will be scheduled based on your body’s internal clock measured on the first visit at the research unit. On day 2, you will be given 3 meals and a snack at specific times. You will also drink a beverage with dinner that contains a non-radioactive “tracer” that allows us to see how your body handles fat in your diet. On day 3, you will be served breakfast. You will not be allowed to bring or eat your own food and snacks during the study.
What are the risks of the study?
Blood tests: Taking blood may cause discomfort, bleeding or bruising where the needle enters the body. In rare cases, it may result in fainting. There is a small risk of infection. The amount of blood we are taking is less than the amount of blood collected during blood donation.
DEXA Scan: A DEXA measures your bone density and body fat content. A DEXA scan is similar to an X-ray, but uses much less radiation than a normal chest X-ray (about 10%). X-rays and gamma rays can damage cells, but at low doses, the body is usually able to repair these cells.
Isotope ingestion: The isotopes you receive are naturally occurring compounds, and are not radioactive.
Can I get the results of the tests involved in this study?
Yes. We will send you the results by mail or e-mail as soon as all of them are available. We can also send the results to your provider at your request for future reference.
How does payment for the study work?
You will be paid $875 for completing all parts of this study. You will be paid $100 for the first visit at the research unit. You will be paid $225 for each of the 3 overnight visits and $25 for the DEXA scan. You will receive an additional $75 at the end of the study, if you come to all your visits without schedule changes. Parking costs are also reimbursed. You will have an option of receiving a check by mail or direct deposit 3-4 weeks after all of your visits are finished.
Dinner Time Study 