Chocolate was considered a health food until early last century, with a range of potential benefits. It was used thousands of years ago by the ancient Mayans and Aztecs, then by Europeans between the 16th and 19th centuries, as an ingredient in cures for many illnesses, including fevers, liver disease, kidney disorders, dysentery, constipation, and to foster needed weight gain.

Perhaps underlying its current role on Valentine’s Day, the original chocolate drink was used by the Aztecs as an aphrodisiac and some European doctors in the 1700 and 1800s said chocolate made people amiable and “incited consumers to… lovemakingâ€.

There is increasing scientific evidence that a little bit of chocolate each day may do you good. But as you may already know, when it comes to your health, all chocolates were not created equal.

Nutritional properties
It is relatively simple to compare your favourite kind of chocolate by looking at the Nutrition Information Panel found on nearly all foods. The below list shows the nutrient composition of the more common varieties in a 25 g serve, which is equivalent to half of one row of a large block (350g) of chocolate, or half a small bar.

All chocolates are relatively high in energy (kilojoules), mainly because of their fat content. Most are also a good source of carbohydrates, primarily because added sugars help mask chocolate’s naturally bitter flavour. The exception is the new stevia-based chocolate bars that use polydextrose instead of carbohydrate to provide texture and bulk.

• Chocolate bar, milk, with nuts: Energy (544kJ), Fat (7.4g), Saturated fat (3.6g), Carbohydrate (13.3g), Sugars (11.2g), Fibre (1.2g)
• Chocolate bar, milk: Energy (539kJ), Fat (6.9g), Saturated fat (4.2g), Carbohydrate (15.5g), Sugars (13.9g), Fibre (0.2g)
• Chocolate, dark: Energy (540kJ), Fat (7.1g), Saturated fat (4.3g), Carbohydrate (15.7g), Sugars (13.0g), Fibre (0.3g)
• Chocolate, milk, with nuts and fruit: Energy (545kJ), Fat (7.4g), Saturated fat (3.6g), Carbohydrate (13.3g), Sugars (11.2g), Fibre (1.2g)
• Chocolate, milk, caramel filled: Energy (498kJ), Fat (6.2g), Saturated fat (3.8g), Carbohydrate (15.4g), Sugars (13.4g), Fibre (0.1g)
• Chocolate, dark, fondant-filled: Energy (434kJ), Fat (4.0g), Saturated fat (2.8g), Carbohydrate (17.0g), Sugars (16.8g), Fibre (0.5g)
• Chocolate, liqueur-filled: Energy (418kJ), Fat (3.9g), Saturated fat (3.6g), Carbohydrate (15.0g), Sugars (14.7g), Fibre (0.7g)
• Chocolate, carbohydrate-modified, plain, non-nutritively sweetened: Energy (402kJ), Fat (7.0g), Saturated fat (4.3g), Carbohydrate (15.5g), Sugars (1.4g), Fibre (0.2g)
• Chocolate, dark, stevia-sweetened with polydextrose: Energy (496kJ), Fat (10.8g), Saturated fat (6.6g), Carbohydrate (1.4g), Sugars (0.1g), Fibre (6.5g)

What about weight gain?
Most chocolates are what we call energy dense, with lots of kilojoules in a relatively small volume. This is good if you are trying to gain weight, travel long distances with limited storage space, or participate in an endurance sport where it is advantageous to carry around a concentrated and highly palatable source of carbohydrate and energy.

However, high energy density is obviously not good if you are trying to lose weight. In contrast, most non-starchy vegetables provide less than a quarter and most fresh fruits provide less than half of the energy per serve as chocolate, and they are much higher in water and fibre so they tend to be more filling.

Cholesterol and fats
Chocolate is high in total and saturated fats. In high-quality chocolates, cocoa butter is the main source of fat. Cocoa butter is high in stearic acid, which of all the saturated fats raises the ‘bad’ LDL cholesterol the least and also raises the ‘good’ HDL cholesterol more, so the net effect on your total blood cholesterol level is not bad at all.

However, the amount of cocoa butter used in chocolate varies, as does the amount of the stearic acid, and this information isn’t usually provided clearly on the packaging. As a rough guide, the better-quality and, as a result, more expensive varieties generally have more cocoa butter, so are usually a better choice.

Effect on blood glucose
Despite the relatively high carbohydrate (sugar) content of most chocolates, they don’t have as large an impact on blood glucose levels (BGLs) as expected, unless of course you overindulge. Chocolate contains around 15 g of carbohydrate per 25 g serve (with the exception of the new stevia/polydextrose-based chocolate bars that have less than 2 g per serve), which is within the recommended range (15–30 g of carbohydrate) for a snack or dessert.

Also, the glycemic index (GI) of chocolate is low, with an average value of 45 for most local brands. This is because of the high fat content, which slows the rate that the sugars are released from the stomach into the intestine and absorbed into the blood. So overall, the glycemic load is less than 10 (low) for a typical serve of most common varieties.

So provided that they don’t overindulge, people with diabetes do not have to eat low/reduced-sugar chocolates to avoid high BGLs. But while the low carbohydrate stevia/polydextrose varieties will have the least effect on BGLs, they are relatively high in fat and consequently have nearly the same amount of kilojoules as regular varieties, so are not much better for losing weight. Other kinds of alternatively sweetened chocolates usually provide less kilojoules — although they are usually more expensive and often not as tasty as sugar sweetened chocolate.

There is a good argument that you should have a little bit of what you enjoy, or, “If you really like chocolate and don’t wish to over-consume the product, always choose your favourite!â€

The antioxidants
Along with green and black tea, red wine, certain fruits (e.g. berries, black grapes, plums, apples) and vegetables (e.g. artichoke, asparagus, cabbage, russet and sweet potatoes), chocolate is one of the richest sources of a powerful group of antioxidants known as flavonoids. Flavonoids are thought to possess several properties that may benefit people with diabetes or pre-diabetes, including helping to prevent cholesterol accumulating on artery walls, relaxing major blood vessels and thus decreasing blood pressure, and perhaps even reducing the ability of the blood to excessively clot. Half a row (25 g) of dark chocolate provides about the same amount of these antioxidants as half a cup of black tea or a glass of red wine. Note, however, that milk chocolate contains only one third as many antioxidants as dark chocolate, and white chocolate contains none at all.

Dr Alan Barclay, BSc, Grad Dip, PhD, APD, AN, is Head of Research, Australian Diabetes Council and Chief Scientific Officer, GI Foundation

This article was originally published in Conquest Magazine, published by Health Publishing Australia