Tricks foods play
The Eldest points out this article by Janet Raloff in Science News:
Most people would never equate downing a well-dressed salad or a fried chicken thigh with toking a joint of marijuana. But to Joseph Hibbeln of the National Institutes of Health, the comparison isn’t a big stretch.
New animal experiments by Hibbeln and his colleagues have recently shown that the body uses a major constituent in most vegetable oils to make its own versions of the psychoactive ingredient in marijuana. Called endocannabinoids, these natural compounds play a role in heightening appetite. So overproducing them unnecessarily boosts hunger, similarly to how pot triggers the munchies (SN: 6/19/10, p. 16).
If what happens in people mirrors what happens in animals, then the prevalence of soybean oil, corn oil and other polyunsaturated vegetable oils in today’s Western diet means your body is “dumping out a lot of these marijuana-like molecules into your brain,” explains Hibbeln, a nutritional neuroscientist. “You’re chronically a little bit stoned.”
Vegetable oil’s link to endocannabinoids is just one example of newfound and surprising ways that foods can confuse calorie-sensing networks and foster obesity — in some cases by damaging the brain. Especially troubling: Excess body weight itself can exaggerate the risk of the brain telling a well-fueled body that it is running on empty.
By understanding what messes with the body’s satiety meters and why, scientists hope to identify tactics for reducing a diner’s likelihood of becoming another statistic in the obesity epidemic.
Energy in the balance
Responsibility for monitoring calorie input and energy output falls to the brain. And the job is not easy, says endocrinologist Michael Schwartz, director of the University of Washington’s Diabetes and Obesity Center of Excellence in Seattle.
To maintain a constant weight, a 160-pound man would need to consume “about 1 million calories over the course of a year,” Schwartz explains — “and expend almost exactly that same million calories.” Only by integrating hosts of chemical signals day and night can the brain manage this energy-budgeting feat, which it has done quite well for most people throughout most of history.
Though scientists once thought the body controlled appetite through a process of error correction, they now know that . . .