A new study shows that obesity does not always go hand in
hand with metabolic changes in the body that can lead to diabetes, heart
disease and stroke.
Scientists found that a group of obese people does not have
common metabolic abnormalities associated with overweight, such as insulin
resistance, abnormal blood lipids, high blood pressure and excess liver fat.
In addition, obese people who had no metabolic issues when
the study began did not develop them even after they gained more weight.
The study involved 20 obese participants. They were asked to
gain about 15 pounds over several months and the study examined how the extra
pounds affected their metabolic functions.
"Our goal was to have research participants consume
1,000 extra calories every day until each gained 6 percent of his or her body
weight. This was not easy to do. It is just as difficult to get people to gain
weight as it is to get them to lose weight," said first author Elisa
Fabbrini, MD, PhD, assistant professor of medicine.
Before and after weight gain, each subject's body
composition, insulin sensitivity and ability to regulate blood sugar, liver fat
and other measures of metabolic health were carefully evaluated.
The evaluation finds that the metabolic profiles of obese
subjects remained normal if they were in the normal range when the study began.
However, the metabolic profiles significantly worsened after weight-gain in
obese subjects whose metabolic profiles already were abnormal.
"This research demonstrates that some obese people are
protected from the adverse metabolic effects of moderate weight gain, whereas
others are predisposed to develop these problems," said senior
investigator Samuel Klein, MD, the Danforth Professor of Medicine and
Nutritional Science and director of Washington University's Center for Human
The study is important clinically because about 25 percent
of obese people do not have metabolic complications. The data shows that these
people remain metabolically normal even after they gain additional weight.