But the real secret may be in what Dan calls the "Mesoamerican trifecta" that is the predominant diet in much of Central America—and has been for 3,500 years! The diet consists of lightly salted corn tortillas, beans and squash. "It's arguably the best longevity food ever invented," Dan says.
Another important aspect of the Nicoyan diet is that they tend to eat their larger meals in the morning, with progressively smaller meals throughout the day. This not only leaves Nicoyans craving fewer calories during the day, it also lets them transition into sleep much more easily when darkness falls. "A hundred years ago, when the sun went down, the brain would start making more melatonin. And with more melatonin, you'd get tired, you'd get drowsy," Dr. Oz says. "Today, the reason half of us don't sleep normally is because the last thing we see is a computer screen or the tube. That actually does the opposite to your brain—it stimulates it. So of course you can't fall asleep. You've got to glide to sleep."