How the annual ratings guide affects a restaurant's bottom line.

Credit: Axel Bueckert / EyeEm

The annual unveiling of the Michelin Guide and its star-anointed list of restaurants is one of the most anticipated events in the dining calendar. A lot of fuss has been made in the past few years over the guide's coveted star ratings—and for good reason!

"Michelin is the global currency," restaurateur Ahmass Fakahany, who co-owns Ai Fiori and Marea with Chef Michael White, told Vanity Fair last November. "People are flying into New York from Asia, from Latin America. It's a marker for the global traveler. I have yet to see someone who has one who hasn't hung it up in their restaurant."

While a favorable multi-star rating in the latest Michelin Guide means that a restaurant will likely experience a boom in business, it's been nearly impossible to quantify—publicly, in currency, beyond just a sense of sheer terror and dread—what the loss of a Michelin star could mean to a restaurant. Until now.

Thornton's restaurant in the Fitzwilliam Hotel in Dublin, Ireland, held a Michelin star until 2015. According to a report in the Irish Independent, over the course of the year since the restaurant lost its Michelin star, profits declined 76 percent—down to €12,472 year-over-year from €53,510 in the 2013-2014 fiscal year. In fact, since losing its star-rating, the restaurant's revenue has declined so much that it closed in late October 2016.

"After I lost it, I felt like someone had stabbed me in the heart," chef-restaurateur Kevin Thornton told the Irish Times this fall. Chef Thornton had previously been a Michelin-star chef for 20 years. "You put your heart and soul into this every single day and when someone criticizes you and says you are not good enough, it feels like you have failed. But you have to tell yourself: 'It is what it is.' Negative energy doesn't produce anything good so why swell on it if you don't need to?"

While Chef Thornton plans on launching a new dining project in the spring of 2017, some chefs haven't been as lucky. Following the loss of one of his three Michelin stars in 2003, Chef Bernard Loiseau of La Cote d'Or in Burgundy, France, committed suicide after a lifelong struggle with depression.