In Nicoya, Costa Rica, people have eaten this plate for breakfast, lunch, and dinner for generations. It looks humble. Nutritionally, it’s anything but. Rice and beans, eaten together, form a complete protein: all nine essential amino acids your body can’t make on its own — from two simple plants, no meat required. Now add it up. Fiber from the beans and whole grains. Healthy fats from a few slices of avocado. Slow-digesting complex carbs instead of refined ones. Together they make a meal that helps keep blood sugar steady, keeps you full for hours, and feeds the gut bacteria tied to a longer, healthier life. The Nicoyans call it gallo pinto — “spotted rooster.” I call it one of the best longevity foods on earth. Beans are the cornerstone of every blue zones diet: the people who eat about a cup a day tend to outlive the people who don’t. No supplements. No complicated plan. Just two of the cheapest foods in the world, eaten together — the way the world’s longest-lived people have a...