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.
AdvertisementIn 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 Nutrition.
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.