Energy Expenditure and Gastric Bypass Surgery Study

The aim of this study is to assess whether the energy you burn daily increases after you have
bariatric surgery. Until now, there hasn't been an effective way of measuring all activity on
a daily basis. Physical Activity Monitoring System (PAMS) has been created just for this
purpose. PAMS is a garment that can be worn under your clothes, that records body position
and movement through space. We will use the PAMS along with special water to measure your
total daily energy expenditure right before surgery, and again 6 months and 24 months after
surgery.

Study subjects will be initially recruited from OHSU IRB-Approved advertisements. Interested
study subjects will be screened through an informal telephone interview. If there are no
health conditions that exclude participation, subjects will be asked to give IRB-approved
consent.

Subjects will be consenting to undergo three 18 day phases. Each phase will consist of 15
daily visits to the Clinical & Translational Research Center (CTRC), and 3 full day and
nights in the CTRC. The CTRC day visits will be 1 hour visits, where subjects will shower,
replace their dirty PAMS with a clean PAMS, have their weight measured and be asked to walk
on a treadmill for a total of 12 minutes with 3 minutes each at 0.0, 0.6, 1.6 and 2.4 mph.
Subjects will be asked to drink special water on Day 2, and daily urine samples will be
collected for 14 days. On Day 16 subjects will undergo a series of Energy Expenditure tests
using a breath analyzer. Subjects will begin with lying for 30 minutes, then sitting for 20
minutes, standing for 20 minutes, and a transitional period of standing and sitting for 20
minutes. Subjects will then be asked to walk for three 15 minute intervals at 0.8, 1.6, and
2.4 mph. Day 17 will be a repeat of Day 16 but will be followed by Dual Energy X-Ray
Absorptiometry (DEXA) or BodPod (for individuals over 350 lbs) which is device which uses the
movement of air to measure your muscle and fat volumes. Day 18 subjects will begin with lying
for 30 minutes,then be given a breakfast to eat. Their breathing test will then continue
every 15 of 30 minutes after eating breakfast to assess how much energy their body burns
during digestion, for 450 minutes (7.5 hours).

PAMS allows physical activity to be measured precisely during daily activities. By attaching
sensors (inclinometers) to the torso and thigh, body posture can be defined:

Lying: torso and thigh sensors indicate horizontal, Standing: torso and thigh sensors
indicate vertical, Sitting: torso sensor = vertical, thigh sensor = horizontal. Duplicate
sensor sets are used in all subjects to gather duplicate data every ½ second for 14 days. The
physical activity data are combined with the breath measurement data to allow us to measure
all forms of activity. The following are key features; specialized sensors (accelerometers)
are completely integrated with the inclinometers so that data on body position and movement
are continuously gathered; the sensors are attached to the subject using a harnesses that
allows a full range of daytime and nighttime physical activities as well as bathroom use.

Data analysis is simple requiring a standard PC that runs Excel and written macros programs.
Once this data is downloaded, it will be sent to Mayo Rochester where it will be analyzed for
the following:

- Time-spent lying, sitting, standing and walking,

- Average accelerometer output for non-walking activities (lying, sitting and standing).

- Average accelerometer output for walking and,

- Number of transitions made between postures (e.g. 'sitting-to-standing'). Breathing
feedback will be used to calculate, in duplicate measurements of the Energy Expenditure
(EE) of sitting, standing, transitions and walking at 0.8, 1.6 and 2.4 mph.

Posture and activity EE data collection. For the physical activity monitoring period (Days
2-15), the EE for sitting, standing and transitions will be calculated by multiplying the
time engaged in each activity (or number of transitions) by the EE for that activity.

Non-Exercise Activity EE = EE sitting + EE standing + EE transitions + EE walking.

The special water will be measured in the urine collected daily. The daily urine samples will
be shipped to and analyzed by University of Wisconsin's special instrument in Dr. Schoeller's
lab. This special water has the ability to tell us your total energy expenditure over the
whole day. The special water has a marker or label attached to the water molecule. The
special instrument reads how many water molecules possess this special label. Body water
excreted through urine can tell us a person's total daily energy expenditure.

Inclusion Criteria:

- No acute illnesses

- Weight less than 227 kg (limit of Bod Pod and Treadmill)

- Able to walk at 2.4 mph for 15 minutes (needed for the energy expenditure testing)

- No tobacco use

- Ability to stop alcohol consumption during test phases

- For female subjects; no plans for pregnancy in 24 months and menstrual cycles of 21-35
days

- No history of eating disorder

- No history of current substance abuse

- No history of chest pain or shortness of breath at rest or on exertion.

- Negative pregnancy in women.

Exclusion Criteria:

- Informed consent not obtained

- Prior bariatric surgery

- Unlikely to comply with follow-up protocol (e.g., travel time from home too long to
make visits feasible, unwilling to return for follow-up visits)

- Unable to communicate with local study staff

- Lactating women