Starbucks lovers will soon be rudely reminded that there are 520 calories in a venti, whole milk pumpkin spice latte.

Hold the whipped cream and you're still knocking back 440 calories.

Such nutritional information is already available on the Starbucks website, but starting Sept. 29, Canadians will see the caloric reality of their morning routines when they order drinks from the till. The changes for food drink items come into effect Nov. 2.

​​The U.S.-based coffee giant already posts calorie counts on menu boards south of the border, but this will be a first for Starbucks Canada.

Bryan Bollinger, a Duke University marketing professor, was a PhD candidate at Stanford University in California when he published a study about the effects on people's behaviour of posting calorie totals on Starbucks menus. (Duke University)

The movement began in 2008 in the Big Apple, but according to a study several years ago out of Stanford University's School of Business in California, it didn't change coffee-buying habits.

"There was zero effect for drinks," said Bryan Bollinger, who crunched the numbers and published his findings in the American Economic Journal in 2011 when he was a PhD student at the university.

"I found drinks that were 700 calories … but it seemed that consumers already knew that," he told the Calgary Eyeopener on Friday.

Starbucks gave Bollinger access to "several hundred million observations" — every single transaction made on customer loyalty cards at locations in New York City, Boston and Philadelphia between January 2008 and February 2009.

The data was anonymous, but allowed him to compare the behaviour of coffee lovers who visited stores that did and did not have calorie posting on menus.

Topped with whipped cream, a venti whole milk pumpkin spice latte has 520 calories. (Starbucks/Facebook)

Bollinger, who now teaches marketing at Duke University in Durham, N.C., found that the extra information did not deter people from buying high-calorie drinks, and only had a "small" influence on their pastry-eating habits.

"Consumers reduced their calorie content by six per cent on average from food items and two-thirds of that was people choosing not to buy a pastry item and just forgoing it altogether," he told the Eyeopener.

"When we ran surveys, we found that people had been systematically underestimating the calories in the food items and they weren't underestimating the calories in the drink items. So that really shows how important consumers' prior beliefs are about the calorie content if we are to expect an effective calorie labelling."

With files from the Calgary Eyeopener