For some people cheese can seem as addictive as chocolate, especially when it's melted.
To meet these cravings for all things cheddar, brie and parmesan, a slew of restaurants have popped up recently that focus specifically on selling cheese-based dishes.
But is it wise to run a company that relies so heavily on one type of food? And isn't all this cheese-eating bad for our health?
Both had lost their office jobs and, in what many would consider a risky move, chose to put their life savings into the venture.
But seven years on the decision is paying off.Image copyrightThe Great American Grilled Cheese KitchenImage caption
The pair have opened two outlets in San Francisco, and sales are increasing 7% every year at their flagship outlet, and 35% at the newer site.
They serve around 16 varieties of grilled cheese sandwich, ranging from the classic recipe to ones with fancy cheeses and experimental fillings, such as hickory-smoked turkey, apricot-jalapeno relish and lavender-basil pesto.
Mr Pollak now plans to franchise his brand across the US. But isn't he worried that his somewhat limited product range might one day go out of fashion?
"I can still remember making my first when I was three, using the toaster oven in my house."Image copyrightThe Mac FactoryImage caption
It's all part of the "fast casual" dining trend that has swept the world in recent years, says Josh Benn, global head of food and retail at Duff & Phelps, a corporate-finance consultancy,Image copyrightThe Mac FactoryImage caption
Since it launched in 2014 the business has opened three outlets to meet demand, says owner Graham Bradbury.
"Cheese is coming back into fashion. Everything is melted-cheese this or melted-cheese that. Lots of companies are starting up and it does feel quite competitive."
Mr Bradbury recognises a hot food trend when he sees one. According to research firm Horizons, macaroni and cheese was five and a half times more likely to appear on restaurant menus in the 12 months to February 2016 than in 2010.
Some of the cheese dishes in the spotlight have roots that go way back - and perhaps worryingly for those serving them, they have tended to go in and out of fashion over the years.
Take the Swiss dish fondue, a shared pot of melted cheese into which groups of diners dip vegetables, charcuterie and bread. It is thought to have first been made in 1699, and saw spells of popularity in the 20th century, including in the US in the 1960s where it was enjoyed at parties.Image copyrightGetty ImagesImage caption
Recently though retailers have been offering cook-at-home fondue sets, newspapers have been publishing recipes, and more restaurants are offering the gooey dish.
London's St Moritz, which has served fondue since 1974, claims to sell up to 20,000 servings of fondue every year.
Boss Armin Loetscherm doesn't seem concerned that it might fall out of fashion again.
"I think it will always have fans because of its communal aspect, as people are sharing and interacting with each other all the time."
It was typically only found in Canada, where it is a national dish, but today restaurants from New York to London, and Paris to Melbourne serve it as well.Image copyrightGetty ImagesImage caption
While loved by fans, however, some varieties of poutine can contain as many as 1,500 calories - just 500 short of the recommended daily intake for the average adult female. And other cheese-focused dishes can be similarly unhealthy.
"It's a leading source of saturated fats, and is associated with a higher risk of getting heart disease and even Alzheimer's."
He also points out that cheese can be addictive, thanks to its high concentration of casein, a protein that can ignite your brain's opioid receptors.
"And when it's melted, cheese has a smell that can be even more tempting," says Dr Barnard.
More worrying, he feels, is the tendency for companies in this space to focus only on one type of specialist dish.Image copyrightGetty ImagesImage caption
For now, it doesn't look like the appetite for cheese is waning. Britons eat around 27 grams of cheese per person per day, and other European countries often consume twice that amount. Americans are big fans too.
For this reason, Mr Pollak believes businesses like the Great American Grilled Cheese Kitchen will keep growing. He points to the success of sandwich chains such as Tom + Chee and the Melt Shop which now span the US.
"I strongly believe that a grilled cheese concept could be as big as a Chipotle [which has more than 2,000 branches globally]," he says.
Source : http://www.bbc.com/news/business-42164538