What does the future look like for the biggest guns in the fast food industry? You’d be forgiven for thinking, from the evidence of the last few years, that it’ll be an endless cycle of a diminished bottom line and playing catch-up while the twin trends of healthy food and premiumisation chip away at the market. That’s a difficult game for them to play - so difficult that Jeremy Corbyn risked £30,000 of sponsorship money by rejecting the chain’s plans to have a stand at the Labour conference promoting British farm produce.

Farm-sourced and healthy isn’t necessarily the only way, though. A huge new McDonald’s outlet in Missouri – dubbed The McDonald’s of the Future by franchise owner Chris Habiger – plans to fly in the face of received wisdom. Its unique point of difference? All-you-can-eat fries.

We’re not talking a lower-salt, reduced-calorie option here. We’re talking a bottomless deep-fried proposition.

You may think Habiger is one spud short of a sack, but he could well be on to something. Amid all the public pressure and handwringing over the state of the public’s waistline, there’s room for a counterintuitive manoeuvre – embracing the supersize.

When McDonald’s was caught on the back foot by the Morgan Spurlock documentary that launched a thousand imitators, it responded by dropping its largest portions. Now its Missouri franchisee is bringing a buzz by offering the largest possible portion.

You can see the same dynamic in the half-disgusted/half-impressed breathless reports on American fast food like Pizza Hut’s hot dog in a pizza crust or Taco Bell’s Cheesy Gordita Crunch (a taco inside a flatbread), or KFC’s bizarre chicken sandwich which uses more chicken instead of bread. They generate buzz. They generate column inches.

What unites the Taco Bell, Pizza Hut and KFC examples? All three brands are owned by Yum! Foods, they’re all in growth, and none of them is embracing health trends. Who goes to a fast food place for a salad and a low-calorie lemonade? When you think fast food, do you think healthy lifestyle choices or do you think indulgent treat? Exactly. Unlike other fast food brands (including McDonald’s at an overall corporate level) that are trying to square their wares with healthier eating trends, Yum! is marketing to a younger crowd with a knowing wink, and that crowd is responding.

In fact, light-heartedly turning ‘unhealthiness’ into an ironic marketing trait can become a brand in itself. Want an indulgent treat? How about chunks of doughnut coated in kids’ cereal?

There’s an accepted place for a luxury indulgence now and again, and if fast food is too busy trying to tempt the healthy, clean-eating crowd in, it’s in danger of missing the point entirely.