Chris Voigt, executive director of the Washington State Potato Commission, has eaten nothing but 20 potatoes a day for the past two months.
He did it to debunk perceptions that potatoes are unhealthy and instead are a good source of fibre, potassium and vitamin C.
To that end, he's eaten nothing but 20 potatoes a day - no cheese toppings, no butter and milk for mashing - since 1 October. He's had them baked, chipped, boiled, steamed, mashed, fried - and for Thanksgiving last Thursday, he feasted on mashed potato formed into a turkey shape, and pumpkin pie made with - you guessed it - mashed potato with pumpkin pie flavouring added.
Nutritionist Fiona Hunter agrees that potatoes have a bad reputation. "Although many people think potatoes are nothing more than starch carbs, they are a surprising source of several vitamins and minerals. However, eating just potatoes will not provide all the nutrients needed for good health."
Critics had warned Voigt it would lead to weight gain, loss of energy and worryingly high blood sugar levels from all the carbohydrates.
But in the course of his two-month diet, Mr Voigt himself says he has lost 18 pounds. His previously borderline-high cholesterol has dropped - down 52 points at the half-way mark.
"Physically I feel great. Lots of energy, sleep good at night, no strange side-effects," says Voigt. "I'm not encouraging anyone to go on this crazy diet, nor would my doctor. This diet was just a bold statement to remind people that there is a lot of nutrition in a potato.
"My doctor is interested to see the final results, and he suspected I would be just fine at the end of 60 days."
While nutritionist Sue Todd wouldn't recommend such a diet, she says it has more going for it than some - especially if he was in reasonably good health to start with, and doesn't continue beyond 60 days.