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Does Chocolate Help You Sleep?

By Spencer Hyman  ·  18th July 2020  ·  The Science of Chocolate

For most of its history we’ve “drunk” chocolate.  And hot chocolate remains a favourite “night cap” for many kids and adults.

Yet many people fear that eating, or drinking, chocolate in the evening will keep them up at night.  And one of the most common questions at our Virtual Tastings remains “does chocolate contain caffeine”.

The simple answer to that “is there caffeine in chocolate” question is YES.  But the amount of caffeine in chocolate depends on the type of chocolate, the cocoa varietal, how it’s farmed and how it’s crafted (or processed).

The more contentious question is “does chocolate at night keep you from sleeping” (or “will some chocolate in the afternoon act as pick me up”).  To try and answer this question, we’ve researched some of the active ingredients in chocolate and tried to understand their impact. 

Our conclusion is that the answer differs not just depending on the chocolate but on the person eating (or drinking) the chocolate. 

Chocolate’s Active Ingredients

Chocolate contains a bunch of active ingredients – in particular caffeine, theobromine and tryptophan. Chocolate is also normally combined with sugar and sometimes milk. Each of these “work” on us differently.

Caffeine works directly on our central nervous system making us more “alert” and, when overdone, make us jittery and it can even become addictive with unpleasant withdrawal symptoms.  There is some caffeine in chocolate.  But it’s not a huge amount, even in dark chocolate — far less than in a cup of coffee.  Savouring a few squares of chocolate will involve consuming less  caffeine than in drinking a cup of decaffeinated coffee.  To become addicted to the caffeine in coffee it’s suggested you need to drink more than 9 coffees of Xg per day; for chocolate it’s over ten 100g bars per day.

Chocolate contains far more of another stimulant, theobromine.  In a standard dark chocolate bar, theobromine comprises 1-2.5% of the weight of a bar, caffeine 0.06-.4%.  Theobromine, even though it’s in the same class of chemical as caffeine (and is just as astringent), doesn’t stimulate the central nervous system.  Rather it acts as a muscle relaxant whilst also stimulating, and regulating, cardiovascular activities (i.e., it can sort your heart out).  Unlike caffeine there is no evidence that Theobromine will keep you awake – indeed there are studies suggesting that theobromine can help people sleep (see blog for references).

Chocolate also contains tryptophan, which  stimulates serotonin and melatonin.  And serotonin and melatonin are believed to help sleep.  But again, the amount of tryptophan differs by chocolate type and it impacts different people very differently. 

Now let’s turn to some other stuff that is often added to chocolate — sugar and milk.

Sugar for almost everyone acts as a stimulant which prevents most of us from going to sleep (at least initially).  That’s why people reach for a sugar snack (including many chocolates) for a mid afternoon pick me up.

Milk, especially hot milk (for drinking chocolate) however is soporific.

Differences Between Chocolates

Just to make matters even more complicated, different chocolate types contain different amounts of each of these elements. See the blog for more details, but here is a first summary

  • Dark chocolate contains the most theobromine, caffeine and tryptophan but has the least sugar (normally) and no milk
  • White chocolate (ie just the cocoa butter) contains no caffeine, but does have theobromine, tryptophan and lots of sugar and milk (or coconut milk if it’s vegan etc.)
  • Milk chocolate is between the two …. 

And then different beans, farming practises and crafting approaches also make massive differences.  For example; different roasting profiles and fermentation approaches will impact the concentration (and efficacy) of tryptophan. 

Differences Between People

As if this complexity isn’t enough, it turns out that different people react differently to the same bars and compounds.  For more on this see the work done by Professor Tim Spector (an avid craft chocolate fan and subscriber) on identical twins where he shows how the way we react to different foods is primarily a question of our gut’s microbiome.  And this is definitely applicable to chocolate

Our Request, Experiment and Suggestion

Given all this complexity, we’d like to ask for your help with an experiment.  Can you find a friend, family member, partner, etc. and experiment with different chocolates at different times and record your reactions here?

Sources:

ACADEMIC ARTICLES

https://www.netdoctor.co.uk/healthy-eating/news/a26374/dark-chocolate-magnesium-levels-sleep-help/

https://jcsm.aasm.org/doi/10.5664/jcsm.5384

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4335269/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3575938/

JOURNALISTS

https://mammothcomfort.com/does-chocolate-really-stop-you-sleeping/

https://www.sleep.org/articles/five-surprising-foods-that-could-be-making-you-tired/

https://www.cacaoteaco.com/blogs/blog/does-chocolate-have-caffeine

https://criobru.com/blogs/news/what-is-theobromine-and-should-i-swapping-it-for-caffeine

https://www.discovermagazine.com/health/caffeine-vs-chocolate-a-mighty-methyl-group

OTHER SOURCES

http://www.tim-spector.co.uk/

https://joinzoe.com/