Believe it or not, chocolate is a healthy treat, as long as you choose wisely. Dark chocolate is rich in flavonoids, antioxidants that have been shown to lower blood pressure, improve blood flow, and boost overall heart health. Choose chocolate that is at least 70 percent cacao or cocoa to optimize the antioxidant power and health benefits. Dark chocolate may even boost your mood. While there's no scientific explanation for why, the rich taste and sensuous mouth-feel of a decadent piece of dark chocolate may be to thank. Just be sure to keep your portions in check — one ounce of dark chocolate has about 150 calories.