If there’s one thing that people love more than chocolate, it’s science claiming that chocolate is good for you. The most recent is a study that found a link between eating chocolate and improved cognitive performance. However, given how much fat and sugar most chocolate also contains, are the reports of its benefits worth taking seriously?

Makes you cleverer

This new study, based on nearly 1,000 people from New York, is not the first to link chocolate to brain function, but what it actually tells us remains very vague. “It’s not possible to talk about causality, because that’s nearly impossible to prove with our design,” said one of the researchers, meaning that we can’t tell whether clever people like chocolate or chocolate makes you clever. Or indeed if there is something messier going on.

Helps weight loss

Can this really be true? It was certainly widely reported last year, but in fact, the news turned out to be a scam, perpetrated by the science journalist John Bohannon to prove how susceptible the media is to pseudoscience. Bohannon did conduct a real trial with some people eating chocolate and some not, but he measured so many things about them that he knew some sort of fluke “effect” would probably show up. And what do you know? The chocolate-eaters happened to lose weight; the abstainers didn’t.

Prevents heart attacks and strokes

There are mountains of research papers claiming this to be true. Some, such as a 2012 analysis of 37,103 Swedish men, look quite authoritative, showing that the rate of stroke among middle-aged and older men was 17% lower among those who ate a lot of chocolate, despite controlling for other factors. Still, the results weren’t statistically significant. And eating a lot of chocolate certainly is a good way to become unhealthily overweight – probably better to hold off the Dairy Milk for now.

Improves fitness

Research from UC San Diego suggests that chocolate might act as a kind of performance-enhancing drug – until you look at the detail. The 2011 study is really about a compound called epicatechin, which is present in chocolate, and its effect on mice, who are not people. Epicatechin dramatically improved the endurance of the mice while they were running on a treadmill. Whether this would translate to humans isn’t known, but even if it did, you’d probably need such a tiny dose of epicatechin that it would be like eating half a square of chocolate. Any more and the effect might be reversed. It also has to be dark chocolate – epicatechin is destroyed by the process of making milk chocolate.