Feb. 14, Valentine's Day, celebrates love. 

And we mark the day with thousands of kilograms of candy hearts, chocolate — and other confections like red velvet cheesecake with sweet raspberry coulis. 

Of course our collective sugar lust doesn't last just one day; Canadians consume about 40 kilograms of sugar every year, according to Statistics Canada. That's roughly 110 grams — more than 20 teaspoons — of sugar eaten each day, per person, across all ages in this country. 

In fact, one in every five calories we eat comes from sugar, in one form or another. 

But our penchant for sweets is by no means a new desire. Sugar has driven economies and changed the world. 

There was even a time, 100 years ago, when people ate more sugar than we do currently. Back then, per capita consumption of sugar by a Briton was nearly 45 kilograms. 

The root cause of the human sweet tooth

It's theorized that as mammals, the taste for sweet begins with breast milk. As we evolved from the great apes we also discovered how much we liked the sweetness found in honey and fruit.

We learned quickly that ripe fruit was the choicest and sweetest and provided a good source of energy needed to survive. Sugar activated our brains and made us feel good, too. 

Eventually, over millions of years, human beings learned how to process sugar cane cheaply and it became easily accessible. 

Historically hooked on sugar

In Shakespeare's England, in the 16th and 17th century, sugar was featured in about half of the 2,100 recipes recorded in cookery books of the time.

In wealthy homes, sugar sat on a cook's table in two-kilogram "loaves" to be scraped or chiseled off as needed. 

Nobles even used sugar in their dental hygiene — though without much success. The result was aristocratic teeth rotted a lot quicker than a peasant's because they could afford more sugar. 

Sugar was an ingredient and a condiment used cavalierly, in all courses of a meal, in a time before distinctions were made between sweet and savoury. 

Sugar's unsavoury past

Of course, sugar and slavery are intricately linked. It was constantly brought in on ships from the New World. 

It's estimated roughly 13 million slaves were brought from Africa to the Americas and Caribbean to harvest sugar cane between 1500 and 1850. 

It is said that sugar mill construction, helped develop the technological skills needed for a nascent industrial revolution by the early 17th century. 

But at quite a human cost.