New research suggests that obesity is tied to structural changes in the brain, making it especially hard for overweight people to keep extra pounds off.
Study author Michael Schwartz, of the Diabetes and Obesity Center at the University of Washington in Seattle, and colleagues looked at the brains of rats on a high-fat diet. They were surprised to find that the rats’ hypothalamuses became inflamed within 24 hours of the switch in diet.
This inflammation is a typical reaction to injury, the researchers said. Scientists have known for about five years that overweight animals tend to have an inflamed hypothalamus.
The researchers found the same signs of hypothalamic neuron injury when they used brain imaging on obese humans.
“To explain a biologically elevated body weight ‘set-point,’ investigators in the field have speculated about the existence of fundamental changes to brain neurocircuits that control energy balance,” Schwartz said, as reported by Psych Central.
“Our findings are the first to offer direct evidence of such a structural change, and they include evidence in humans, as well as in mice and rats.”
These structural changes may explain why people have such a hard time keeping weight off once they’ve lost it, the researchers concluded.
“Our data would point to a more structural, biological basis for why it is difficult to keep weight off,” Schwartz said, as quoted by Voice of America News. “It has to do with damage to the brain area that is responsible for controlling body weight.”
The study appears in the Jan. 3 issue of the Journal of Clinical Investigation.