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(CNN) -- "I'm in shape," a friend of mine repeatedly quips at the gym. "Round is a shape."
It's an old joke, but there may be some truth to it. A new study
published this week in the European Heart Journal shows it is possible
to be both obese and healthy.
"It is well known that obesity is linked to a large number of chronic
diseases such as cardiovascular problems and cancer," lead study author
Dr. Francisco Ortega said in a statement. "However, there appears to be
a sub-set of obese people who seem to be protected from obesity-related
Researchers analyzed data from 43,265 participants in the Aerobics
Center Longitudinal Study, which was done between 1979 and 2003.
The participants' body fat percentages were determined using
hydrostatic weighing (submersion in water) or skinfold measures, and
their fitness levels were tested on a treadmill. Using these criteria,
29.7% of the study participants were labeled obese. Of the obese, nearly
half were considered "metabolically healthy."
All of the participants were followed until 2003; 1,779 died during that time period.
What's metabolically healthy mean?
Your metabolic health is determined by several factors: High blood
pressure, high triglycerides, low HDL - or good - cholesterol and high
fasting glucose levels. For this study, a participant was considered
metabolically healthy if they displayed zero or only one of the above
Ortega and his colleagues use several terms to describe the study
participants who were obese but metabolically healthy. They call it
"uncomplicated obesity" or "metabolically benign obesity." Basically
that means the obese individuals saw few negative health effects of
their extra weight.
The researchers found that the metabolically healthy but obese
participants had a 38% lower risk of dying than their metabolically
unhealthy peers. There was also no risk difference between the
metabolically healthy obese and the metabolically healthy normal weight
"Our study, together with previous literature, strongly suggest that a
better cardiorespiratory fitness will make you healthier regardless of
your weight status," Ortega told CNN. "These findings clearly support
the notion that doing exercise and improving fitness might be an
effective public health tool for fighting against obesity."
As in any research, there are limitations to the conclusions drawn
from the results. Insulin resistance - a precursor of diabetes - was not
measured in the study participants. The data also did not show how long
the participants were obese, which can be an important predictor of
metabolic risk, according to the study authors.
Still, one thing is clear to Ortega: "Exercise benefits everyone,
regardless of fitness and fatness level. So exercise should be
encouraged by doctors to all the patients."