Does Eating Chocolate Cause Insomnia? (Research Review)

Chocolate is considered a “stimulating” food in sleep research.

Most reviews on insomnia include a conclusion such as (1):

Avoid eating or drinking much during the hour or two prior to retiring; in particular, avoid stimulating foods (e.g., chocolate, especially dark chocolate) or beverages (e.g., coffee, tea, cocoa, cola drinks).

On top of insomnia, too much chocolate at the wrong times can cause sleep disorders like REM sleep behavior disorder (RBD) that lower overall sleep quality (2).

There are 3 main issues with chocolate that can contribute to insomnia symptoms:

1. Caffeine
2. Theobromine
3. Sugar (situational)

This post will quickly summarize the most important research on each of those points.

The Effect of Caffeine in Chocolate On Sleep

Not everyone knows that there’s caffeine in chocolate, but most people know that caffeine can cause insomnia (3).

There’s not as much as in coffee, but still a significant amount, especially if you already consume caffeine from coffee or tea (although note that most tea is good for insomnia).

How Much Caffeine is In Chocolate?

Unfortunately you won’t find the amount of caffeine on the labels of most products that contain chocolate. In the U.S. for example, it’s not required on most food and beverage products (4):

Instead, we’ll need to rely on the measurement of caffeine in general categories of chocolate products by researchers.

For reference, know that there’s about 100 mg of caffeine in an average cup of coffee.

Caffeine in Cocoa and Chocolate Bars

The amount of caffeine will vary by brand.

According to research, this is the amount of caffeine in different types of “plain” chocolate bars and powder (5):

• Dark chocolate - 0.38 mg of caffeine per g
• Semisweet - 0.88 mg/g
• White chocolate - 0.19 mg/g
• Cocoa powder - 2.30 mg/g

It’s not surprising that cocoa powder has the highest caffeine content, since bars are essentially diluted powder.

It’s a bit surprising that semisweet chocolate generally has more caffeine than dark chocolate. I’m not a chocolate expert, so I can’t tell you why that is.

To put this into reference, a Lindt chocolate bar is usually about 100 grams. If it’s dark chocolate, there’s about 40 mg of caffeine in it. Most people won’t eat an entire bar at a time of course.

But having half a chocolate bar a bit before bed? It certainly won’t help sleep.

SummaryThere’s a significant amount of caffeine in dark chocolate and semisweet bars. Depending on the serving size and if it's eaten close to bedtime, it could interrupt sleep. White chocolate is best if you’re looking to limit caffeine intake.

Caffeine in Cereals With Chocolate

What about foods that contain some cocoa powder in them?

One study looked at the caffeine content in a few popular cereals and snacks that contain chocolate (6):

In case that’s hard to read, there’s 2.3 mg of caffeine in a 30 gram size of cocoa puffs. But most people eat at least 200 grams of cereal in a serving, so the caffeine load will be more like 14 mg or more.

SummarySnacks that contain chocolate typically have less caffeine than directly eating a chocolate bar, but can still contain a significant amount. Remember to factor this into your overall caffeine intake.

Caffeine Content in Chocolate Drinks

Finally, let’s look at the amount of caffeine in common food products, mainly beverages (7):

In an 8 oz drink of hot chocolate (236 mL), there’s just 5 mg of caffeine.

SummaryCompared to foods that contain chocolate, drinks with chocolate flavor don’t contain much caffeine.

Theobromine in Chocolate

The research on theobromine is very lacking, so it’s not surprising that most people aren’t aware of it.

For now, we know that theobromine is a mild stimulant and is found in significant quantities in chocolate. Note that caffeine is quite a bit more potent still.

Theobromine is actually a byproduct of caffeine metabolism. On top of the theobromine found in chocolate, your body produces more as it breaks down caffeine.

While more research needs to be done, one study found (8):

Theobromine is much weaker than caffeine or entirely inert in these situations.

So caffeine is still the main concern when it comes to chocolate and sleep quality, but theobromine may play a small role.

Theobromine Content in Chocolate Foods

You won’t find theobromine content listed on the labels of food.

Instead, let’s turn to the research again for the amount in common chocolate foods (9):

SummaryThe amount of theobromine is about proportional to the amount of caffeine in chocolate products, so everything we looked at above in the caffeine section still applies.

Sugar Content of Chocolate

Sugar certainly isn’t healthy, and there is some research that suggests that sugar can contribute to insomnia.

A few grams in a dark chocolate bar won’t have much of an effect, but sugary cereals and sweet chocolate can often contain enough to affect your sleep quality.

This brings us to a nice summary point: The amount of chocolate eaten is the most important factor.

SummaryHaving a small square of chocolate an hour before bed likely isn’t a big issue for most. But having half a bar or more can have a significant impact.

Should You Avoid All Chocolate?

There’s nothing wrong with chocolate. There is a problem with consuming too much chocolate in the hours leading up to sleep.

Research shows that flavonoids in chocolate exert neuroprotection and cardiovascular benefits that are good in many ways. They may even protect against impairment after sleep deprivation (10).

So there’s no reason to cut chocolate out of your diet completely.

Instead:

• Limit chocolate consumption to reasonable amounts
• Eat chocolate as early as possible
• Limit other caffeine sources like coffee
• Avoid chocolate sources that are particularly high in sugar

Studies suggest that for most people, keeping caffeine intake under 200 mg per day doesn’t increase the risk of insomnia (11).

References

1. Behavioral interventions for insomnia: Theory and practice
2. Exacerbation of REM sleep behavior disorder by chocolate ingestion: a case report
3. Caffeine intake reduces sleep duration in adolescents
4. Caffeine Content Labeling: A Missed Opportunity for Promoting Personal and Public Health
5. HPLC determination of caffeine in tea, chocolate products and carbonated beverages
6. Improved analysis of theobromine and caffeine in chocolate food products formulated with cocoa powder
7. Insomnia: An Ignored Health Problem
8. Comparative stimulant and diuretic actions of caffeine and theobromine in man
9. Theobromine and caffeine content of chocolate products
10. Flavanol-rich chocolate acutely improves arterial function and working memory performance counteracting the effects of sleep deprivation in healthy individuals
11. Risk Factors for Incident Chronic Insomnia: A General Population Prospective Study