Chocolate Won’t Cure Your Heart Disease

Why eating 6 bars of chocolate a week is unlikely to help your health

There’s something magical about eating chocolate. It’s hard to compare the experience to anything else; the wonderful silkiness of the block as you place it on your tongue, the burst of flavour as it slowly dissolves in your mouth, the sweet and smoky aftertaste it leaves behind long after it’s gone.


So it’s not surprising that we love chocolate. We love eating it. We love drinking it. We love mixing it into every dessert ever.

You may have noticed the media going crazy about how great chocolate is for your heart over the last few days. Headlines like “Chocolate may prevent irregular heart beat” from, “Six bars of chocolate a week could cut risk of common heart condition” from The Telegraph and “Chocolate linked to lower risk for heart condition AFib” from CBS paint a wonderful story that we are all dying to hear.

We love being told that chocolate is good for our health.

Even when it probably isn’t.

Big Wonderful Study

The Big Wonderful Study is the positive version of the Big Scary Study, where the media takes a piece of reasonably everyday research — in this case looking at whether chocolate has a very specific health benefit — and turning it into the Best News Of The Year.

Everyone has jumped on the bandwagon of chocolate being good for you, some even advocating that people start eating more chocolate in response to this study.

Unfortunately, getting your health advice from tabloids can be risky.

Because they were all pretty far off the mark.

Pictured; not a doctor

Chocolate And The Heart

We all want to be told that our bad habits are actually good.

The headlines are all based on a recently-released study that looked at a large population of people, divided them into groups based on chocolate consumption, and looked at their risk of being diagnosed with a condition callled atrial fibrillation (basically a problem with your heart rhythm).

Scientists; great at research, not as great at snappy titles

It was a pretty cool study. The researchers looked at a very big population of people (~55,000 individuals), and stratified the population into 4 groups; low, medium, high and very high intake of chocolate, all based on how much people said that they ate.

We all want to be told that our bad habits are actually good.

So far, so good.

The researchers collected a whole bunch of measurements on everything from education level to BMI. They then did some great multivariate analysis to compare chocolate consumption with atrial fibrillation. This is a cool statistical trick that allows you to look at whether factors other than the study factor (in this case, chocolate) influenced your outcome (atrial fibrillation). So you can tell that, for example, it’s unlikely that the participants’ level of education influenced the results.

As you’ve no doubt heard, they found that, compared to those who ate the lowest amount of chocolate, people who had a medium or high intake were 17% less likely to get sick!

So chocolate is great for your health after all?


Pictured; medicine?


Unsurprisingly, the media got it wrong when it comes to chocolate for your heart. The Big Wonderful Study wasn’t so wonderful after all.

The first thing I noted when I looked at the study is that the people who eat the least chocolate of all were very different to the rest of the groups. They had higher blood pressure, smoked more, were more likely to have diabetes, and were less likely to have achieved a high level of education.

They were very different to the rest of the study groups

Now, the researchers used some cool statistical tricks to control for these specific variables, but there are hundreds of other factors that could’ve caused the effects that they saw. People who eat basically no chocolate might be different to everyone else in a whole heap of ways; what if they’re all really unhealthy and they’ve cut chocolate out temporarily to lose weight? What if they’re really poor and can’t afford expenses like chocolate in their diet?

What if they are actually eating a lot of chocolate, but since they are trying to lose weight they feel guilty admitting to it? Remember, this was all based on self-report, and people lie about what they eat on a regular basis.

What if they are actually eating a lot of chocolate, but since they are trying to lose weight they feel guilty admitting to it?

From this study, it’s impossible to know. Add to that the fact that the researchers actually ran quite a number of tests, of which only a small handful were significant, and you’ve got some serious problems. If chocolate prevented heart disease, you’d expect to see that the more people ate, the better off they were. Instead, the researchers found that certain groups of chocolate-eaters were healthier, but many of them were not.

And on top of that, the researchers didn’t actually look at overall heart health; they looked at the diagnosis of a single condition. Saying “chocolate is good for your heart” based on this study is like saying that being run over by a car is good for your health because you get a really deep massage as the wheels roll over you.

We know that having more sweet, fatty food is bad for us. It’s incredibly well confirmed literally everywhere. So even if chocolate reduces the incidence of one heart condition, we’d need to know a lot more before recommending people eat more of it because it might cause a whole bunch of other problems.

Sounding bad?

Sadly, it gets even more idiotic.

Read. The. Study.

I can’t stress enough how important it is to actually read the study before you write about it. It’s freely available, not that long, and actually pretty decent reading.

If any journalists had actually read the study (or even the press release), they would’ve noticed this passage:

It is not that hard to find

The researchers literally said that they didn’t prove that chocolate is good for you. And yet most journalists decided to ignore the advice of the scientists doing the research and recommend chocolate as a healthy choice.

That’s pretty shoddy reporting.

Journalists are rushed. They have a difficult job with tough deadlines and often no training in the matters they are covering.

But when even the press release that you are quoting disagrees with you, it might be time to go back and have another look.

Chocolate is one of the most delicious things that humans have ever created. The smell, the taste, the indescribable experience as that first piece caresses your tongue is simply unbelievable.

But it isn’t healthy.

Enjoy your chocolate, eat to your heart’s content. But don’t believe the hype. It probably isn’t any better for you than any other delicious sugary food.

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Epidemiologist. Writer. Podcaster. Twitter FB Email

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