Even yong children know that chocolate is a treat, to be savoured on special occasions.
But the "dark" variety, which has more cocoa, is touted as healthier and even as a health-booster.
Dark chocolate, it is suggested, can alleviate all manner of problems,
from high blood pressure to depression, while improving mental acuity.
Many studies, often paid for by Big Chocolate, hint this may be true.
Sadly, the best research debunks the idea.
Dark chocolate's purported benefits are ascribed to compounds called flavanols,
which are particularly abundant in cocoa.
In randomised controlled trials (the gold-standard type of study)
researchers have looked at the health effects of capsules containing flavanols,
as well as of consuming flavanol-rich foods such as cocoa products, coffee, tea, berries, grapes and apples.
Some trials have found beneficial effects, for example on blood pressure.
But results overall have been inconsistent.
Moreover, these trials typically last just a few weeks,
so they may not reflect the consequences of sustained consumption.
Observational studies, which ask about diet rather than dictating it,
have sometimes found that those who eat more flavanols,
either from various foods or specifically from dark chocolate, are healthier.
They are less likely to develop diabetes, for example.
But such individuals may have other things going for them, too