Chocolate isn't just a high-fat, high-sugar food with 'empty' calories like many others. It actually contains many substances that are good for the cardiovascular system:
> Tannins are part of the family of polyphenols, specifically flavonols, which have antioxidizing properties and fight the free radicals which damage tissue and cause cardiovascular problems.
> Vitamin E, beta-carotene and copper, which are also antioxidants.
> Potassium, which reduced blood pressure.
> Cholesterol-reducing hypocholesterolemiant fats. Dark chocolate is particularly high in these.
Some studies claim that just a small amount of chocolate (less than 10g a day, or 1 square) is enough to reap these benefits.