If you're trying to wean yourself off the excesses of the Christmas period, a modest amount of dark chocolate every day could be the healthiest way to do it.
Dark chocolate that's rich in flavanols can improve heart functions. It was tested on 11 patients after they had a heart transplant, and it helped their new hearts work better. It can also reduce high blood pressure, especially during the early stages of the problem. People with hypertension (high blood pressure) found the chocolate helped as part of their daily diet.
But that's where the good news ends. The same can't be said for milk or white chocolate, and it's only true of dark chocolate that is high in flavonols.
(Sources: Circulation, 2007; 116: 2376-82 (transplant study); Journal of the American Medical Association, 2007; 298: 49-60 (hypertension study)).