Want to eat for science? Recruiting starts this month for the first test in humans of whether higher-caloric diets spur MRI-detectable inflammation in the hypothalamus, the brain structure that regulates body weight.
Researchers already know that a "highly energetic" diet causes mice to develop inflammation in this brain region, and that these cellular-level inflammatory changes precede weight gain, said Dr. Ellen Schur, who directs the University of Washington's Nutrition and Obesity Research Center.
"We think that this inflammation is part of the pathway that promotes energy storage and weight gain," said Schur, a professor of medicine at the UW School of Medicine.
She aims to enroll 42 participants in this pilot study. Enrollees will be randomly assigned to one of three diets: one whose meals are 130% of estimated daily caloric needs, one whose meals are 150% of estimated daily caloric needs, and a control group whose meals are 100% of daily caloric needs.
Participants will be provided all meals for a 14-day span and will be asked to strictly adhere to their prescribed diets. Meals will be essentially the same across the three groups. During the first seven days, the foods will be high in sugar, saturated fat, and calories; for the second week, participants will eat a lower-calorie regimen.
The thermostat-like hypothalamus is home to neurons that sense nutritional availability, based on dietary intake, and communicate with other areas of the brain to regulate the body's energy balance by affecting appetite and metabolism.
During the two-week study period, participants will need to travel multiple times to UW Medicine's campus in South Lake Union to pick up meals and to undergo brain MRI scans, the latter of which will enable the researchers to see whether they can detect changes in enrollees' hypothalamus in concert with the dietary changes.
"Our hypothesis is that, when humans are undergoing a stimulus (diet) that's high in energy, or calories, they will also develop signs of inflammation in this body-weight regulating area of the brain," Schur said. "We know that happens in rodents, but we do not know if that happens in humans."
This pilot study's small enrollment is by design: Researchers want to understand not only whether brain structures change, but also how well participants tolerate a week of overfeeding and make sure the two-week diet regimens don't spur any longer-term effects on health or body weight.
Prospective enrollees must meet specifications for age (20-40 years), body mass index (25-29.9 kg/m2) and other health criteria. Enrollment information is posted; find additional study details at clinicaltrials.gov
