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The Science of Chocolate: What Makes It so Addictive?

K S Lane is a student of science and is deeply passionate about educating others on her favorite topics.

Chocolate is a sweet treat enjoyed daily by hundreds of millions of people across the globe, and if you’ve ever sampled a bite of this tasty morsel it’s not hard to see why it’s so popular. The smooth, rich, sweet taste of chocolate is almost intoxicating and leaves you wanting more and more, until suddenly you’re sitting with an empty packet in your hand and wondering how you managed to eat an entire block of the stuff in two minutes. Believe me, we’ve all been there. In fact, a poll conducted in 2016 found that chocolate is the 16th most loved food ranked globally, beating out burgers, chips, fruit, curry and (not all that surprisingly) salad. But why, exactly, is chocolate so beloved by billions across the globe? Between seemingly wild rumours of chocolate being an aphrodisiac and an antidepressant it can be difficult to sort out fact from fiction when it comes to the science of the treat. Below I’ve answered a few commonly asked questions about chocolate and explained why you can’t seem to get enough of it.

Once you've started to eat chocolate, it's difficult to stop.

Once you've started to eat chocolate, it's difficult to stop.

First, What's Chocolate Made of?

The ingredient that gives chocolate its flavour is called cacao. Cacao is is sourced from the fermented fruit of, you guessed it, the cacao tree. These trees are grown in regions close to the equator, like Papua New Guinea, Indonesia, Ghana, Brazil and Mexico. The main chemical component of cacao is called theobromine, which is a compound similar to caffeine in that it is also a mild stimulant. Theobromine is also a vasodilator, which means that it causes blood vessels to expand and blood pressure and heart rate to drop when ingested. In sum, it’s a stimulant that makes you feel relaxed. Still with me?

By itself, cacao (or cocoa) powder doesn’t taste all that great. Therefore, other ingredients are added to chocolate to make it palatable. This consists of sugar (like, a truckload of sugar) and cocoa butter. The other ingredients depend on the type of chocolate. For the darker varieties, these three ingredients are pretty much it. For milk chocolate, milk powder is added. For white chocolate, the cacao is taken out, which is why some consider it 'fake' chocolate. In my opinion, I don’t care what it’s called as long as it tastes good, but some are scarily passionate about this distinction.

A map showing the major cacao growing areas of the world. Cacao trees flourish in warm, equatorial climates.

A map showing the major cacao growing areas of the world. Cacao trees flourish in warm, equatorial climates.

How Long Have People Been Eating Chocolate?

Most historians suggest that people have been consuming chocolate for around 2000 years. Note the distinction between 'consuming’ and 'eating,’ as for the majority of its history chocolate was drunk in a liquid form. It was only in the mid 1800s that chocolate was developed in a powdered form, and in 1847 the first chocolate bar was created by Joseph Fry. A few years after companies such as Cadbury and Nestle appeared and became the pioneers of the emerging chocolate industry.

What Makes Chocolate so Addictive?

There are a few theories about why chocolate is so addictive, ranging from the fairly obvious (like the idea that the sugars and fats in it keep you coming back for that sweet taste) to the unexpected. A particularly interesting theory proposed by a group of scientists who fed chocolate to rats suggests that the drug enkephalin may be key in creating so-called chocoholics. Enkephalin is a natural brain chemical, but the researchers found that levels surged unnaturally high after the rats consumed chocolate m&ms. This is significant because enkephalin triggers opioid receptors, the very same ones activated by drugs such as morphine and heroin. Basically, eating chocolate heightens your levels of enkephalin, and heightened levels of enkephalin lead you to want to eat more chocolate. In the study conducted the rats gorged themselves on about 5% of their body weight in chocolate, which is equivalent to an average human eating about three and a half kilos of m&ms! Thankfully, it seems like humans are less susceptible to enkephalin than rats, but the vicious circle of addiction is still clearly evident in many people in regards chocolate.

One theory as to why chocolate is so addictive relates to a spike in levels of a chemical called enkephalin.

One theory as to why chocolate is so addictive relates to a spike in levels of a chemical called enkephalin.

Are Some Kinds of Chocolate More Addictive Than Others?

The research regarding this isn’t entirely clear. Presuming that the enkephalin spike after eating chocolate is due to some kind of chemical in cacao, theoretically dark chocolate would be more addictive than milk chocolate, which contains lower levels of cacao, and white chocolate would barely be addictive at all considering it has no solid cacao. However, other factors come into play regarding addiction. The sugar and fat content in white chocolate is much higher than in dark chocolate, so people may find it more difficult to stop eating that particular variety. Regardless, your personal favourite chocolate is most likely to be the one you find the most addictive.

Is Chocolate Actually an Aphrodisiac?

Yes. Sort of. Theobromine, which you’ll recall is a component of cacao, has been known to have a mildly sexually stimulating effect on some men. There was a study into whether chocolate increased women’s libidos and at first the results seemed promising, but when the data was adjusted for age it found that chocolate had little to no effect.

Does It Actually Help With Depression?

There have been many studies linking chocolate to increased levels of serotonin (a feel good chemical), and research has shown that people with depression eat almost twice the amount of chocolate as those without a diagnosis. However, this doesn’t necessarily mean that chocolate functions as an antidepressant. There is no conclusive evidence that it has a positive long term effect on mental health, and it’s important to remember that though it tastes good, chocolate isn’t good for the body. Eating it to excess in order to feel better will lead to nasty consequences like obesity and heart disease, which would stack the odds against someone already trying to manage their depression. Chocolate is a nice occasional treat and as such can make you feel good, but eating it as a replacement for actual medicines is dangerous and unwise.

Having a nibble of some chocolate is sure to raise your mood for a bit. In the case of clinical depression, however, actual medicine is a lot more helpful than sweet treats.

Having a nibble of some chocolate is sure to raise your mood for a bit. In the case of clinical depression, however, actual medicine is a lot more helpful than sweet treats.

In Summation

Chocolate is delicious, and there’s lots hiding behind the smooth brown surface of your average chocolate bar. Having been consumed for over 2000 years, its key ingredient is cacao, which is grown in tropical areas close to the equator. Cacao contains the chemical theobromine, which is a mild stimulant and vasodilator. There are a number of theories as to why the sweet treat has addictive properties, one of which relates to the action of a chemical called enkephalin, which binds to opioid receptors in the brain. Chocolate has been found to have an aphrodisiac effect in some men, but no concrete evidence has been produced as of yet to indicate its effects on women. It also does promote the release of serotonin in the brain, but has no long lasting effect on depression and should never be eaten as a substitute for antidepressants. All in all it’s a pretty cool food and a great after dinner treat.


For each question, choose the best answer. The answer key is below.

  1. For how long have humans been consuming chocolate?
    • 2000 years
    • 3000 years
    • 1500 years
  2. As observed in rats, which chemical spikes in the brain after chocolate consumption?
    • Acetylcholine
    • Levadopa
    • Enkephalin
  3. Where do cacao plants best thrive?
    • In desert regions
    • In equitoiral regions
    • In cold climates
  4. What stimulating chemical is found in cacao?
    • Theobromine
    • Enkephalin
    • Caffeine
  5. Studies have linked chocolate consumption to increased levels of what 'feel-good' hormone?
    • Dopamine
    • Enkephalin
    • Serotonin
Scroll to Continue

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Answer Key

  1. 2000 years
  2. Enkephalin
  3. In equitoiral regions
  4. Theobromine
  5. Serotonin



© 2018 K S Lane


K S Lane (author) from Melbourne, Australia on June 28, 2018:

Pamela- at least you like dark chocolate, which is reasonably healthy, and not other kinds!

Pamela Oglesby from Sunny Florida on June 28, 2018:

I love dark chocolate, and I wish I did not like any chocolate due to the calories. I think this is an excellent article.

rabi on March 08, 2018:

I am a dark chocolate fan but avoid to eat alot of chocolates

Readmikenow on March 01, 2018:

Very well written. I am a huge fan of chocolate. Enjoyed reading this.

Jorge Cruz from Canada on March 01, 2018:

Just to complete the spectrum of fans: I am a dark chocolate person...

K S Lane (author) from Melbourne, Australia on March 01, 2018:

I'm a milk chocolate fan myself, Louise, but I can appreciate white now and again too.

Louise Powles from Norfolk, England on March 01, 2018:

I don't eat chocolate all that often, but when I do I prefer white chocolate.

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