When Blood Sugar Becomes an Excuse for Chocolate: What British Researchers Discovered

Chocolate as part of a blood sugar-friendly diet? It sounds too good to be true, and in its sugary, milky supermarket form it is. But when British scientists looked closely at what nearly 2,000 women actually ate, they found something surprising: those who regularly ate foods rich in certain plant pigments, the same pigments that colour berries deep blue and red and are found in herbs, red grapes and cocoa, tended to have lower insulin resistance and lower markers of inflammation. Insulin resistance is the hidden first step on the road to type 2 diabetes.

"Something's going to kill us all, Dave"

Few people have made type 2 diabetes as relatable as Tom Hanks. In 2013, on The Late Show with David Letterman, the two-time Oscar winner revealed that the high blood sugar numbers he had been living with since the age of 36 had "graduated" into type 2 diabetes. His doctor told him that if he could get back to his high school weight, he could essentially be free of it. Hanks, who weighed about 96 pounds as a teenager, joked that in that case he would simply have to live with diabetes. Behind the joke was a serious change: he lost weight and changed the way he ate, and he has since spoken openly about daily exercise and paying close attention to his diet.

His story shows what most people with high blood sugar eventually learn: there is no single miracle food, but everyday food choices really do add up. And that is exactly where the British research becomes interesting.

What the researchers actually found

In a study published in the Journal of Nutrition, researchers from the University of East Anglia and King's College London described a delicious discovery that may be relevant to the prevention of type 2 diabetes, especially in its earliest stages, when blood sugar is only beginning to drift upwards.

The team, led by Professor Aedin Cassidy, analysed the diets of 1,997 healthy women aged 18 to 76 from the TwinsUK registry. They estimated how many flavonoids each woman ate and compared this with blood tests for glucose, insulin and inflammation. The results, published as "Intakes of Anthocyanins and Flavones Are Associated with Biomarkers of Insulin Resistance and Inflammation in Women", showed that women who ate the most of two flavonoid subgroups had lower insulin resistance:

• Anthocyanins are found in berries, red grapes, red wine and other red or blue fruits and vegetables. Women who ate the most anthocyanins also had the lowest levels of chronic inflammation.


• Flavones are found in herbs and vegetables such as parsley, thyme and celery. Women who ate the most flavones also had better levels of adiponectin, a protein involved in regulating blood sugar.

Importantly, these benefits were seen with amounts that are easy to reach through ordinary food. The authors were also careful to point out that this was an observational study and that more research is needed to know exactly how much of these compounds might be helpful. As co-author Professor Tim Spector noted, it is intriguing that some foods we often think of as unhealthy, such as chocolate or wine, contain components that may be beneficial.

Why blood sugar swings matter

The researchers' interest lies in flavonoids' potential to help keep blood sugar steadier. Frequent sharp spikes and drops in blood glucose are associated with oxidative stress and inflammation, and chronic inflammation is linked to many of today's most common health problems, including heart disease, obesity and type 2 diabetes. Keeping blood sugar on a more even keel is one of the cornerstones of a healthy diet. If you would like to learn about another food that may help, read our article Peas that Mendel didn't know as medicine: the wrinkled variety hides the secret of stable blood sugar.

This is not a small issue. According to the International Diabetes Federation, around 589 million adults worldwide live with diabetes, and the vast majority have type 2. You can read more about this in our article Another pandemic among us ....

What exactly are flavonoids?

Flavonoids are very widespread in plants and perform several functions. We can recognise them by their pigment, as they give flowers and fruits (and less often leaves) their distinctive yellow, red and blue colours. In plants, flavonoids help protect against UV light, pests and disease, and scientists are studying how they may influence the body's response to allergens, viruses and other harmful substances.

Interestingly, the human body treats many flavonoids as foreign substances and works to process and eliminate them. Laboratory studies suggest that this process activates the body's own detoxification enzymes, which are also involved in neutralising potentially harmful compounds. Some researchers believe this may be one of the ways flavonoid-rich diets support long-term health, although much of this evidence still comes from laboratory and animal research and has not been confirmed in humans.

Where to find the most flavonoids

The richest sources of flavonoids include:

• Citrus fruits, especially grapefruit (note that grapefruit can interact with some medicines, so check with your pharmacist if you take regular medication)


• Berries, with blueberries standing out, along with strawberries, blackberries, raspberries and blackcurrants


• Onions, especially red onions


• Parsley, thyme and celery, which are excellent sources of flavones


• Legumes such as beans and lentils


• Green tea


• Red wine, in moderation, and only for adults who already drink


• Dark chocolate with 70% cocoa or more

A word of caution about chocolate: according to HEART UK, much of cocoa's natural flavanol content is lost during processing, so even dark chocolate should not be considered a health food in its own right. The Harvard T.H. Chan School of Public Health also points out that dark chocolate contains caffeine and that some products may contain small amounts of heavy metals, which is one more good reason to enjoy it in modest portions.

The trio: chocolate, berries and cinnamon

Because we know more than 5,000 different flavonoids from various plants, it makes sense to combine several sources rather than rely on just one. The British researchers did not test a specific recipe, but nutritionists have long recommended one simple and tasty combination that brings together different flavonoid groups: dark chocolate, berries and cinnamon.

Cinnamon is a particularly interesting addition. A 2025 review of 28 trials involving around 3,000 people with type 2 diabetes found that cinnamon was associated with lower fasting blood sugar. The evidence remains mixed, however, and as Cleveland Clinic explains, the American Diabetes Association does not recommend relying on cinnamon to lower blood glucose. If you use cinnamon generously and often, choose Ceylon ("true") cinnamon, as the more common cassia variety contains higher amounts of coumarin, a compound that can strain the liver in large amounts.

How to make your flavonoid spoon

The original folk recipe calls for 100 grams of sugar-free dark chocolate mixed with the same amount of strawberries and generously seasoned with cinnamon. Since 100 grams of dark chocolate alone contains roughly 550 to 600 calories, nutritionists today suggest a lighter version:

• 20 to 30 grams of dark chocolate (ideally 85% cocoa or more, or unsweetened), melted


• About 100 grams of fresh strawberries or mixed berries, chopped


• A generous pinch of Ceylon cinnamon

Mix everything together and keep it in the fridge. Nutritionists who have tried this mixture suggest eating a tablespoon or two about 20 minutes before a meal, as many people find it helps take the edge off their appetite. There is some early scientific support for this idea: a review of cocoa and chocolate research describes a study in which both eating and even smelling 85% dark chocolate was associated with reduced appetite.

The bottom line

This research is not permission to eat a chocolate bar after every meal. But it does offer a pleasant reminder that a healthy diet can be colourful and enjoyable. A handful of berries, a sprinkle of fresh herbs, a cup of green tea and a square or two of truly dark chocolate are small, everyday choices that fit perfectly into a balanced, plant-rich diet, alongside regular physical activity and a healthy weight, which remain the most important steps for keeping blood sugar in check.