Feeding Study

The feeding study consists of two 28-day feeding periods separated by a 28 day "washout" period when you will eat your own food. Before the first feeding period, you must complete an information meeting, some at-home activities and a baseline visit.

Feeding Study Information Meeting

We will ask you to attend a meeting at the Prevention Center. This meeting will take about 2 hours. We will:

• review the feeding study in detail
• answer your questions
• offer you samples of the study food
• review the questionnaires to be completed at home
• instruct you to keep a 3-day food record. This will help us know how much food you usually eat.

If you agree to join the study, we will ask you to sign a consent form. We will also set up the dates and appointments for all the study activities.

Before you begin the first feeding period:

At home, you will need to complete the following activities:

• Keep a 3-day food record
• Fill out questionnaires on health, lifestyle, diet and physical activity
• Collect a small stool sample at home and bring it to your Day 1 blood draw. (optional)

We will set up a Baseline Visit at the Prevention Center. This visit will take about an hour. You do not need to fast for this visit so it can be scheduled for the morning or afternoon, whatever fits your schedule.

At the The Baseline Visit we will:

• Review your completed 3-day food record and questionnaires
• Give you a body composition test (DEXA scan).
• Set up feeding study calendar and Day 1 clinic appointment (about 2 weeks later)
• Give you supplies to take home for the first stool collection. For each stool sample collection we will provide you with a kit that makes it easy to collect the sample. It includes a large plastic container that fits your toilet, a flushable bag that is used to line the collection container, disposable gloves, and a small, well sealing tube for you to bring the sample to FHCRC. The stool sample collection is optional. You can decide not to provide a stool sample and still participate in the study.

DEXA scan

A dual energy x-ray absorptionmetry (DEXA) scan uses a low x-ray dose to measure how much bone and body fat you have. You will lie on your back on a padded table for about 15 minutes for the body scan. The total test takes about 30 minutes. The DEXA scan is not painful and there is little risk of radiation exposure. The x-ray dose is very low. Because exposure to even a small amount of radiation could be harmful to a fetus (baby), we will ask women to take a urine pregnancy test before the DEXA scan. At the end of the study, we will give you your DEXA results.

Feeding Study Activities

Each feeding period will start on Monday, Tuesday or Wednesday, depending on your schedule.

You will eat dinner at the Human Nutrition Lab (HNL) Monday through Friday nights and take home breakfast, lunch and a snack for the next day. On Friday night you will take home all your food for the weekend and Monday breakfast and lunch. All uneaten food must be brought back to the HNL to be weighed.

The "washout" period will be at least four weeks between feeding periods when you will eat your own food. The time between the two feeding periods might even be longer, depending on your schedule.

Study Activities during each feeding period (To see a sample study calendar, click here.)

• We will draw some of your blood on the morning of the first study day (Day 1) and on the last study day (Day 29). You will need to fast for 12 hours before each blood draw. We will draw about 65 ml or 4¼ tablespoons each time, for a total of 135 ml or 8½ tablespoons. We will also measure your blood pressure and your pulse.
• On the morning of the first study day (Day 1) of the first feeding period, we will weigh you and measure your waist and hip size using a tape measure. We may ask you to put on an examination gown for these measurements. At all other clinic visits we will weigh you in your street clothes.
• You will eat dinner at the Human Nutrition Lab (HNL) Monday through Friday for two 28-day periods. The dining room is open for dinner between 5:00 and 7:00 p.m. Other times are possible by special request. Each evening we will give you your breakfast, lunch and snacks for the next day. On Friday evenings we will give you the food for the weekend and Monday breakfast and lunch.
• Every time you come in to eat dinner we will weigh you. This is not a weight loss study and we need to make sure that you stay the same weight during the study.
• You will keep a daily physical activity record and food check-off form.
• You will complete questionnaires several times during each feeding period and once each during baseline. The days you complete the questionnaires will vary.
• You will collect all your urine for 24 hours beginning the morning of Day 28 and ending on the morning of Day 29 of each feeding period.
• You will collect a stool sample: once before the first feeding period and then during the fourth week of each feeding period for a total of three collections (optional)
• If you are a female we will ask you to keep track of your menstrual cycle.
• If you agree, do the optional 8-hour Postprandial Test on the last day (Day 29) of each feeding period.