If you can’t stomach chocolate darker than Cadbury’s Bournville (which, at 36 per cent cocoa, is only just classified as dark chocolate), you’ll probably want to swerve the 100 per cent bars popping up on supermarket shelves. Once considered a niche treat for hardcore chocolate lovers, these ultra-dark bars have increased in popularity in recent months, with Swiss chocolatier Lindt being the latest to launch its own version.

If you’re looking to pump some health benefits into your afternoon snack, it might be worth picking up a bar. “100 per cent chocolate contains no added sugar and generally provides a greater concentration of cocoa compounds” that are linked to better heart health, says Nichola Ludlam-Raine, a registered dietitian and author of How Not to Eat Ultra-Processed. “It may also provide slightly more fibre, protein, iron, magnesium and other minerals.”

Here’s everything you need to know about 100 per cent dark chocolate – and which bar to pick up for the biggest health benefit.

What is 100 per cent dark chocolate?

“One hundred per cent dark chocolate is made entirely from cacao,” says Rhona MacFadyen, a senior chocolatier at Hotel Chocolat. The seeds from the cacao pod are roasted and ground to make cocoa, which we know as dark chocolate.

“Every bar of chocolate contains a certain percentage of cocoa – that is, cocoa solids, the dry, dark elements of the bean that give chocolate its flavour, and the naturally occurring fat, known as cocoa butter, that gives chocolate its texture and melting consistency, and mellows the flavour,” says Andrew Baker, author of From Bean to Bar, a Chocolate Lover’s Guide to Britain and judge for the British Academy of Chocolate.

“A simple bar of high-quality 70 per cent dark chocolate will be 70 per cent cocoa solids and cocoa butter, and 30 per cent sugar,” Baker says. “A 100 per cent dark bar has no sugar at all – just cocoa solids and cocoa butter.”

MacFadyen adds that 100 per cent dark chocolate can be intense in flavour, describing the taste as bitter and savoury. “For someone used to sweeter chocolate, it can be an acquired taste.”

The health benefits of 100 per cent dark chocolateHeart health

Flavanols are the reason 100 per cent dark chocolate looks after our heart health. These antioxidants – which give the bar its bitter taste – stimulate the production of nitric oxide. “Nitric oxide helps blood vessels to relax and supports normal blood flow,” Ludlam-Raine says. This is thought to be behind findings that dark chocolate brings down high blood pressure and improves blood vessel function.

“However, most studies have investigated cocoa or flavanol-rich products rather than proving that any particular 100 per cent chocolate bar prevents heart disease,” she notes.

Weight loss

While 100 per cent chocolate contains around 600 calories per 100g (compared with around 540 calories per 100g in Dairy Milk and Galaxy), it can be a satiating snack. “Its intense, bitter flavour may mean some people feel satisfied with a smaller amount, which could make portion control easier compared with a sweeter chocolate that they find easier to overeat,” Ludlam-Raine notes. It’s also low in sugar and higher in protein, with around double the protein content of milk chocolate, which helps you to feel fuller for longer.

Type 2 diabetes

A 2024 Harvard study found that people who had five or more servings of dark chocolate per week had a 21 per cent lower risk of type 2 diabetes, which the scientists believe could be down to the polyphenols in dark chocolate. These compounds – also found in vegetables, fruit, whole grains and coffee – may help improve insulin sensitivity and glucose metabolism.

“We do not yet have strong evidence that eating 100 per cent chocolate directly prevents type 2 diabetes,” notes Ludlam-Raine. However, its lack of added sugar may be helpful if it replaces a higher-sugar product, she adds.

The downsides

100 per cent chocolate is still high in calories (around 600 calories per 100g), and around a third of its weight is saturated fat, which raises cholesterol and, in turn, our risk of heart disease.

However, much of the saturated fat is stearic acid, which appears to have a more neutral effect on “bad” LDL cholesterol than some other saturated fats, Ludlam-Raine notes. Dark chocolate is also a source of oleic acid, which is linked with lower cholesterol and inflammation.