The science of why we love chocolate and strawberries on Valentine's Day

Oysters and champagne are all well and good, and there's a lot to be said for figs and cheese, but one food pairing rules them all on Valentine's Day.

"It's all about chocolate and strawberries this weekend," says Anneke Anhaeusser, head of product development at David Jones Food. "Everyone loves the crunch of chocolate coating a sweet, juicy strawberry. It's a proper match made in heaven."

David Jones usually sells 500 chocolate-coated strawberries a week at its NSW food halls, but in the lead up to Valentine's Day on February 14, the retailer will move more than 5000 of the luxury treats.

Meanwhile in Melbourne, Christos Partsioglou is busy making strawberry balsamic chocolate hearts at Xocolatl in Kew East. "They're our biggest seller, even when it's not Valentine's Day," says the master chocolatier.

"Each heart has layers of balsamic caramel and strawberry ganache. The larger dark chocolate lace heart is very popular too. Chocolate, simply, is the ultimate comfort food."

Indeed, while strawberries are sought-after for their green, fruity sweetness, there is perhaps no food more widely – and intensely – loved as chocolate. But what is it about roasted cacao that delights so many people of all ages?

"If you really delve into the chocolate world, it can be complex like wine, and really exciting to try different varieties," says Xocolatl director Madelaine Partsioglou. "There's a real kind of mysticism about chocolate, not to mention a lovely pleasing feeling when you eat it."

While some studies have linked chocolate to boosting serotonin, high-protein foods such as chicken, eggs and salmon are much better for creating the brain's so-called happy chemical. According to taste and flavour expert Dr John Prescott, much of chocolate's appeal is due to its terrific combination of fat and sugar.

"Any food high in both of those is going to end up being liked," says the author of Taste Matters: Why we like the foods we do, which featured a chocolate-dipped strawberry on the cover until the publisher decided the image was too dark and replaced the chocolate with cream.

"There's also the texture. People quite like textural contrast in food, and chocolate is great for that because you can bite into it, but then it melts in the mouth. Crunchy things with a soft interior tend to be highly liked. This may also explain the extra special appeal of a chocolate-coated strawberry."

Prescott says chocolate's status as a "sometimes food" also contributes to its allure. "From a young age, people receive chocolate as a treat on special occasions such as Easter and Valentine's Day, and that is reinforced all the way through adulthood."

Some retailers and restaurants promote chocolate as a Valentine's Day aphrodisiac – a food to increase sexual desire. However, according to Dr Jessica Danaher, lecturer in nutrition at RMIT University, these aphrodisiac claims aren't supported by science.

"Cocoa products contain many biologically active components, including biogenic amines, that could, in theory, impact a person's arousability," she says. "But there is no biological evidence to show that chocolate is in fact, an aphrodisiac."

What of oysters, mangoes, chillies and other foods purported to be aphrodisiacs though?

Several sexy cookbooks have been published celebrating these ingredients, with titles such as Fork Me, Spoon Me; InterCourses; Intimacy on the Plate and Lust at First Bite. (Recipe highlights in the latter include Tie Me Up Tiramisu, Playful Paella and something called a Puff Pastry Love Log made with leftover curry.)

"It's pretty much all nonsense," says Dr Prescott. "There's no evidence that any food is aphrodisiac, meaning you're more willing to engage in sexual behaviour than usual after eating it."

However, chocolate and any other food ascribed aphrodisiac qualities tends to have a strong placebo effect says Dr Danaher.

"Research shows that just imagining eating chocolate can stimulate the areas of the brain associated with pleasure. Pair that with some strawberries and a romantic snack of a partner, and you're in for a good time.

"And for anyone flying solo this Valentine's Day, I can safely say that chocolate-covered strawberries will at least hit the sweet spot for your taste buds and that's more than good enough."