You don't have to be a gaucho who sleeps atop a pile of bleached cow skulls—Smaug style—to know that red meat has been through the wringer as of late, Paleo horde or not. So it comes with a heavy heart that we announce yet another strike against the true sovereign of carnivores everywhere.
It turns out that we can now add this to the litany of strikes against red meat: It has the ability to make us want to shove even more food in our ever-frothing gobs.
A study from Wake Forest Baptist Medical Center, recently published in the Journal of Clinical Investigation, found that a high dietary iron intake—the equivalent of eating a bunch of red meat—suppresses leptin.
Leptin, as you probably don't know, is the delightful hormone that tells you when you are full. If your leptin is suppressed, you keep yearning for more and more food. Until, next thing you know, you're indulging in a marrow-coated meat orgy. Been there, done that? Now you know why.
The study was based on an animal model. "We showed that the amount of food intake increased in animals that had high levels of dietary iron," said the senior author of the study, Don McClain, who is also the director of the Center on Diabetes, Obesity, and Metabolism at Wake Forest Baptist.
A diet high in iron—esteemed Dr. Atkins be damned—is evidently not too good for you. McClain says, "In people, high iron, even in the high-normal range, has been implicated as a contributing factor to many diseases, including diabetes, fatty liver disease, and Alzheimer's, so this is yet another reason not to eat so much red meat, because the iron in red meat is more readily absorbed than iron from plants."
Sure, other food has iron in it—like beans and spinach. But meat is a prime source of iron.
In the study, two groups of male mice were fed different diets: one high in iron and the other low/normal. The high-iron eaters had a 215 percent increase in iron in their mousy blood. But guess what? Leptin levels in the blood of the high-iron consumers was 42 percent lower that in the low/normal iron group.
Less leptin? More hunger. The mice that had higher iron levels and lower leptin levels desired more food. Thus, determining the correct level of iron in the human diet has become an important goal as we Americans need to control our yen to gorge.
"We don't know yet what optimal iron tissue level is, but we are hoping to do a large clinical trial to determine if decreasing iron levels has any effect on weight and diabetes risk," McClain said. "The better we understand how iron works in the body, the better chance we have of finding new pathways that may be targets for the prevention and treatment of diabetes and other diseases."
So, in the meantime, if you find yourself voracious, lay off the red meat and maybe your leptin will have a chance to tell you that you are, in fact, already full.
Either that or just enjoy your damned meat. And understand that thanks to leptin, your lust to devour may be hard—very hard—for you to control.