Sat 31 Dec, 2011 11:56 am
Study: Brain injury from high-fat foods may be why diets fail
By Carol M. Ostrom / The Seattle Times (MCT)
December 30, 2011
SEATTLE — You’ve heard "a minute on the lips, years on the hips," or some variation. But did it make you put down that frosted butter cookie?
No? OK, here’s another bit of research to snack on: After humans and rodents eat a high-fat diet, their brains begin to show evidence of injuries in just 24 hours. If they keep eating that yummy fatty stuff continuously, the area of their brains that regulates weight — the hypothalamus — will show evidence of serious inflammation and structural damage.
Researchers at the University of Washington and other institutions say they’ve found the first evidence that "hypothalamic neuron injury" is associated with obesity caused by a high-fat diet in rodents and humans.
That may help explain, researchers said, why dieting and exercise often lead right back to a "set weight" for obese individuals.
"Obese individuals are biologically defending their elevated body weight," said Dr. Michael Schwartz, a professor of medicine at the University of Washington and the senior author of the paper to be published in the Jan. 3 edition of The Journal of Clinical Investigation.
Eager to explain why that set point seems to exert so much control over a person’s weight, Schwartz said, numerous researchers have speculated about the existence of "fundamental changes" to brain neurocircuits that control energy balance.
The findings suggest that both in humans and rodents, "Obesity is associated with neuronal injury in a brain area crucial for body weight control," researchers wrote.
Schwartz said the findings show "solid evidence of a change affecting the key hypothalamic area for body weight control with the potential to explain the problem."
Obesity is clearly on people’s minds, and not just for the holidays.
In a survey commissioned by Seattle Cancer Care Alliance and released this week, Puget Sound-area adults singled out obesity as their top health issue of most concern now and in the near future, beating out cancer, heart disease, diabetes, Alzheimer’s and aging.
Obesity topped cancer by greater than 3 to 1 as the most concerning health issue today and by almost 3 to 1 as the biggest anticipated health issue 10 years from now.
In the survey, which reached 600 adults in Puget Sound-area counties, 56 percent said they had gained 10 pounds in the past decade.
Dr. Scott Ramsey, director of SCCA’s Cancer Prevention Clinic, said obesity can put people at risk for several types of cancer, along with diabetes, heart disease and joint problems.
In the brain-injury study, which looked at human brains through MRI scans, researchers said their work was only a step in the right direction, and listed many caveats. They used rodent strains that were genetically predisposed to diet-induced obesity, for example, and similar results might not occur with obesity-resistant strains.
If you’re really set on that butter cookie, you might consider this, too: "We did not prove cause and effect between the hypothalamic neuron injury and defense of elevated body weight — that comes next," Schwartz said.