Health benefits of dark chocolate and how much you should eat

Dark chocolate is particularly beneficial for your gut. It provides fuel and promotes the growth of some of the gut's "good" bacteria. 

But some chocolate is better for us than others. The percentages of cocoa in dark chocolate vary greatly, and scientific studies show that only some dark chocolate, in certain quantities, may have significant benefits.

The cocoa in dark chocolate is a natural source of fiber, vitamins, and minerals, and it has potential benefits for your heart, brain, gut, and overall health.

Dark chocolate has several times more antioxidants than green tea or red wine. And it contains substances that may help lower your blood pressure, improve your cholesterol levels and brain function, and help your body deal with insulin

But some dark chocolate also has high levels of refined sugar and additives. 

This article looks at the potential benefits of dark chocolate. It also discusses what to look for when shopping and how much to eat.

Dark chocolate's health benefits

Good quality dark chocolate has plenty of potential health benefits. Unfortunately, chocolate is also the source of a lot of health myths, and scientists face challenges when studying it, as some of its ingredients may counteract its benefits.

Prof. Tim Spector — scientific co-founder of ZOE and internationally renowned researcher at King’s College London — explained in a recent ZOE Science & Nutrition podcast that chocolate “comes from a plant that is fermented to give it great complexity, so it’s a mixture of fiber and protein, and lots of essential nutrients and defense chemicals called polyphenols.”

How exactly do these molecules in dark chocolate affect your body? Below, find nine health benefits of dark chocolate.

1. Adding nutrients and fiber

Dark chocolate that is at least 70% cocoa has plenty of essential nutrients. It’s high in iron, magnesium, copper, and manganese. It also contains calcium, potassium, and zinc, as well as traces of vitamins A, B, E, and K. 

An average 100-gram bar of dark chocolate has around 11 grams (or 0.39 ounces) of fiber, which is beneficial for your gut health

Most dark chocolate also contains some cocoa butter, a source of the heart-healthy fat oleic acid.

It’s important to keep in mind, though, that chocolate also contains sugars and saturated fats.

2. Providing antioxidants

Antioxidants are compounds in some foods that can help prevent damage to the cells in your body. 

Polyphenols, the cocoa bean’s natural defense chemicals, are a type of antioxidant. 

Some polyphenols are lost during the production process. Still, some cocoa powders have more antioxidants than so-called super fruits like acai, blueberries, and pomegranates, as well as teas and red wines

The potential antioxidant benefits of chocolate are compelling enough that one current study is looking into them on a large scale. 

Working with more than 21,000 people in the United States, the researchers are investigating whether taking a supplement containing a concentrated dose of the antioxidants in chocolate benefits overall health.

3. Helping with gut health

Much like the polyphenols in fruits, nuts, and seeds, those in dark chocolate “are like rocket fuel for your gut microbes,” says Prof. Spector. 

Cocoa is also a prebiotic, a type of fiber that your gut bacteria digest. ZOE scientists have identified 15 "good" gut bugs and 15 “bad” gut bugs associated with better and worse health measures in areas including heart and metabolic health. 

Cocoa can help your “good” bugs flourish, and our research has found that some "good" bugs particularly like dark chocolate. 

“If it’s good quality and has lots of cocoa and not so many of the other ingredients,” then, “Your gut bacteria generally do like chocolate,” Prof. Spector says.

The ZOE-at-home test analyzes your gut microbiome in combination with your blood fat and blood sugar responses to different foods. We can then recommend the best foods for your body and your gut bugs, including “gut booster” and “gut suppressor” foods.

Take our free quiz to find out more. 

4. Supporting heart health and blood pressure 

Flavanols are a polyphenol in chocolate, and theobromine is another natural compound in cocoa. 

Research has linked both to improved blood vessel function, lower blood pressure, and a lower risk of heart disease in people with and without preexisting health conditions.

While many studies have found evidence to support these links, scientists still recommend further research into how these substances may help support heart health.

5. Improving cholesterol levels

Polyphenols also benefit your cholesterol. Studies suggest that they not only increase your levels of "good” cholesterol — they also reduce your levels of "bad” cholesterol and improve your overall levels. 

However, the sugar and saturated fat in dark chocolate can have a negative effect on your cholesterol levels if you eat too much of it. 

6. Boosting brain function?

Research has linked the flavanols in dark chocolate to improved oxygen levels, nerve function, and blood flow in the brain. 

These flavanols are also associated with increased nerve cell growth and activity in brain regions associated with learning and memory, especially the hippocampus. 

Research involving rats suggests that flavanols might offer protection against a decline in brain function and related conditions like dementia and Alzheimer’s. But more studies are needed before we can tell whether this is true for humans. 

7. Lifting mood

Many chocolate lovers believe that chocolate is a mood enhancer, and science suggests that we may be on to something.

The flavonols in dark chocolate stimulate the release of endorphins and help with mental well-being. Cocoa compounds are also involved in the production of serotonin, a neurotransmitter that boosts mood. 

However, some researchers suggest that it will take more studies to show strong links between the substances in chocolate and these effects.

8. Protecting the skin?

Antioxidants are great skin defenders, and some studies suggest that eating dark chocolate that's rich in flavanols could help to protect your skin from UV light damage, as well as have a positive effect on wrinkles and skin elasticity

However, these possible effects are not as well established as some of chocolate's other benefits.

Also, some research links chocolate with worse acne in people who are prone to this condition.

9. Reducing diabetes risk

Scientists have looked into whether flavanols like those in dark chocolate might decrease the risk of type 2 diabetes. 

One large-scale study found that people who ate chocolate more than once a week had a significantly lower risk of developing type 2 diabetes within 5 years, compared with people who rarely or never ate it.

The flavanols in chocolate may influence how your body deals with insulin. Some studies have found that chocolate flavanols may improve insulin production, and others suggest that they could be involved in reducing insulin resistance

What percentage of dark chocolate is healthy?

The percentage of cocoa in dark chocolate is important. The more cocoa chocolate contains, the darker it is, and the more health benefits it's likely to have.

As the cocoa percentage increases, the chocolate is also less likely to contain other ingredients. 

Dark chocolate generally contains 50–90% cocoa. And be aware that some chocolates that look dark have high levels of refined sugar or dairy. 

There’s no consensus about when chocolate starts to become beneficial for your diet, but Prof. Spector recommends opting for chocolate that is at least 70% cocoa.

“If you go for very high cocoa content, then you’re less likely to get anything that’s unhealthy. Pick something with the minimum number of ingredients on the label, and then you know you’re going to get something that is really natural with very little taken away.” 

— Prof. Tim Spector

Are there any risks?

Flavored and lower-cocoa chocolates have more sugar and may also contain artificial sweeteners, as well as emulsifiers to bind the product together. 

Prof. Spector warns that these extra ingredients “are bad for your gut microbes and will actually counteract any of the benefits.” 

Try to choose organic dark chocolate to ensure that any added flavorings are less processed.

Other factors can impact the potential health benefits of dark chocolate. Treating chocolate with alkali (known as Dutch processing) can reduce the cocoa’s naturally bitter flavor, but it also significantly decreases the antioxidant levels

Likewise, the darker the chocolate, the more caffeine it has, which may be an issue if you’re sensitive to caffeine. 

As we mentioned above, the key is moderation. If you eat good quality, minimally processed dark chocolate that’s 70% cocoa or more, negative effects become less likely.

But if you have large quantities of lower quality, highly processed chocolate that contains less cocoa, a lot of extra ingredients, and large amounts of saturated fat and sugar, that’s a different story.

As with any ultra-processed food, eating large amounts can increase the risk of poor health outcomes.

Also, if you have gastroesophageal reflux disease (GERD), experts suggest that chocolate might increase the risk of experiencing symptoms.

How much dark chocolate should you have?

There are no official recommendations about how much dark chocolate to eat for its health benefits. The key is moderation. 

Spencer Hyman, a chocolate expert and founder of the ethical craft chocolate company Cocoa Runners, recommends a “less is more” approach. 

“Try and train yourself to savor rather than to scarf,” he explained in the recent ZOE Science & Nutrition podcast. “It’s much better to have [a little bit of dark chocolate] than scarf some low-fat vanilla yogurt, which has actually got seven times the amount of sugar in it than a dark chocolate bar would have.”

And in scientific studies, participants usually consume small or moderate amounts of chocolate.

One review looking at the effects of dark chocolate found that the researchers had given participants between 20 g (0.7 oz) and 100 g (3.5 oz) each day. 

A more recent review found that most studies had given each participant a maximum of 20 g per day. 

Exactly when you eat chocolate could be important, too. Studies suggest that a small amount of dark chocolate in the mornings or evenings may help stabilize your blood sugar levels by limiting your sweet cravings.

As Hyman says, a small amount of good dark chocolate is “a great way of satisfying your cravings for sweetness at the end of a meal.”

Watch the full podcast below.


Dark chocolate is definitely a treat for your tastebuds. And moderate amounts of minimally processed, high quality dark chocolate may also be good for your health. 

Aim for chocolate that is at least 70% cocoa. This contains more natural fiber, minerals, vitamins, and antioxidants, and fewer other ingredients, like refined sugar and additives.

There is evidence that the nutrients and antioxidants in cocoa — particularly flavanols — may help:

  • boost beneficial gut bacteria

  • improve cardiovascular health, cholesterol levels, mood, and brain function

  • balance insulin production and sensitivity

  • promote healthier skin

However, some scientists believe that more research is needed to back up some of these claims and work out how much chocolate you need to eat to gain the potential benefits.   

An ounce or two of good quality dark chocolate after a meal can be part of a healthy, balanced diet. It can also be a great way to satisfy a sweet craving without taking in too much refined sugar or saturated fat.

The best way to understand what’s good for your body is to learn more about your individual responses to different foods. 

The ZOE program gives you personalized scores for hundreds of foods, based on your unique collection of gut bugs and your blood sugar and blood fat responses after meals. This allows you to truly eat the best foods for your body.

Take our free quiz to find out more.


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