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2002
LSU-HHMI Summer Undergraduate Research Program |
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 Arshin
Sheybani (Lilian de Jonge, Pennington Biomedical Research Center)
A Drop in Delta RQ during an Adaptation to a High Fat Diet
as an Indicator for Developing Obesity
Obesity in humans has become an epidemic in well-developed countries
around the world and is becoming increasingly more difficult
to treat. The objective of this study was to determine whether
certain biochemical, endocrine, and anthropometric characteristic
could be used to predict which individuals are at a higher risk
for developing obesity. In this study 40 healthy, relatively
sedentary individuals with varying age and weight were fed a
standard American diet of 35% fat for three days and then transferred
to a 50% fat diet for another three days. Respiratory quotients
(RQ) were measured using a metabolic chamber, daily blood draws
were taken during the five-day in-patient stay, and anthropometric
characteristics were measured during basic screening. An insulin
clamp procedure was used to determine insulin sensitivity, a
VO2 max test measured physical fitness, and fat tissue biopsies
were preformed to determine adipocyte size. The results showed
a significant correlation (r2 = 0.7834) between the RQ from
the last day of the standard American diet (Day 1 RQ) and the
drop in RQ after being fed on the high fat diet for three days
(delta RQ). Individuals with a relatively high Day 1 RQ demonstrated
the greatest delta RQ. Even though other correlations with delta
RQ were promising, this study is still on going. Muscle tissue
samples along with adipocyte samples were collected before and
after the adaptation to the high fat diet and will later be
analyzed for gene expression. Sympathetic nervous system activity
will later be examined using collected EKGs from heart rate
variability procedures. Thus, several phenotypic characteristics
can be measured to predict which individuals are at a higher
risk for developing obesity.
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