Oct. 3, 2006 -- Ever been so hungry you felt like you could inhale Thanksgiving dinner and keep on eating without missing a beat?
Actually, your brain might be satisfied with a lot less food.
That tidbit comes from a study on rats, not people. The study appears in October's edition of Cell Metabolism.
The findings are "intriguing," write Matthias Tschop, MD, and colleagues in a journal editorial.
"The next meal is not far, and we better start getting ready. According to [the researchers], so will our brain," write Tschop and colleagues.
The study comes from researchers based at Scotland's University of Edinburgh.
They included Louise Johnstone, PhD, who now works in New Jersey at Merck Research Laboratories.
They studied male rats that only had access to food for two hours per day.
After 10 days on that highly restrictive eating plan, the rats were ravenous, devouring food as soon as it became available.
But Johnstone and colleagues noticed something interesting. The rats didn't eat for the entire two hours. They stopped eating at least half an hour before their two-hour deadline.
The scientists examined the rats' brains before and after they started eating.
At feeding time -- but before the rats had the chance to start eating -- the rats showed high brain levels of an appetite-related protein.
That finding suggests that the rats knew it was feeding time and were anticipating their long-awaited chow.
The rats ate "promptly and voraciously," the researchers write. After a few minutes, the rats' brains showed a rise in proteins linked to satiety, which means feeling full.
Those satiety proteins peaked after an hour or 90 minutes of eating, which is when the rats stopped eating.
The rats' mental satiety circuit appeared to be triggered by the first few bites of food, not by a full stomach.