The Check-Up: Hungry? Your Brain Wants Junk Food

Plus, Bobby Flay's slimming down and Sarah Palin might be training for a marathon—today's health headlines

• Ever notice that when your stomach’s growling, you crave junk food? A new study explains that that’s actually your brain talking, not your stomach. Researchers at Yale and the University of Southern California conducted a brain-scan study in which 14 volunteers had MRIs done to see how brain activity changed when blood glucose levels rose or dropped. Here’s where we get all science-y:

When glucose levels were dropped, a deeper area of the brain, which includes the hypothalamus, thalamus and nucleus accumbens, started to light up instead. These areas are related to our emotional or limbic system, and play a key role in motivation, reward and addiction.

This happens because it’s an important survival strategy: when glucose levels wane, it’s a signal that the body is running low on fuel necessary to survive; the response is to remove any barriers to eating. Making food — especially high-calorie goodies rich with glucose — look good is a quick and powerful way to replenish those dwindling reserves.

The study also found that in normal-weight people, the desire for high-calorie foods—and the deep brain activity—diminished as blood glucose levels returned to normal. But in obese people, the brain activity kept going strong, even after the person ate food—so the desire for high-calorie foods never went away. And that, my friend, could lead to some serious overeating. Get the nitty-gritty details here.

• Chef Bobby Flay’s dropped a few pounds over the last year, the Washington Post reports. The chef behind Bobby’s Burger Place says he’s lost between 10 and 15 pounds making only small changes in his diet and eating. Among them: No late-night eating, portion control, and only eating something because it’s absolutely delicious—not just because it’s there. Words to live by.

Runner’s World thinks Sarah Palin might be gearing up for a marathon. Of course, they have no real proof, but writer Amby Burfoot surmises that Palin’s late summer half-marathon finish might mean the former VP candidate has her sights set on a marathon later this fall. If she maintained her impressive half-marathon pace—she finished an Iowa half in 1:46:10—she could run a full marathon in 3:30 to 3:35. Writes Burfoot, “That’s a BQ folks, a Boston Marathon qualifier. It puts her in the top 10 to 12 percent of all American marathoners, on an age-graded basis.”