Washington: Obesity among people who eat a high-fat diet may injure neurons, or nerve cells, in a key part of the brain that controls body weight.
"The possibility that brain injury may be a consequence of the over consumption of a typical American diet offers a new explanation for why sustained weight loss is so difficult to achieve for most obese individuals," said study author Joshua Thaler.
Thaler and his colleagues at the Obesity Centre of Excellence at the University of Washington in Seattle, studied the brains of rodents for the short-term and long-term effects of eating a high-fat diet.
After giving groups of six to 10 rats and mice a high-fat diet for periods from one day to eight months, researchers performed detailed biochemical, imaging and cell sorting analyses on the animals` brains, according to Washington University release.
Within the first three days of consuming a diet that had a similar fat content to the typical American diet, rats consumed nearly double their usual daily amount of calories, Thaler reported.
Rats and mice fed the high-fat diet and gained weight throughout the study. These rodents developed inflammation in the hypothalamus, the part of the brain containing neurons that control body weight.
At the same time, a group of support cells called glia and scavenger cells called microglia accumulated in the hypothalamus and appeared to become activated. Although this collective response to brain inflammation-called gliosis-subsided days later, it recurred after four weeks.
"Gliosis is thought to be the brain equivalent of wound healing and is typically seen in conditions of neuronal injury, such as stroke and multiple sclerosis," Thaler said. "We speculate that the early gliosis that we saw may be a protective response that fails over time."
The results were presented at the Endocrine Society`s 93rd Annual Meeting in Boston.