PORTLAND, Ore. - Pass the fire and gather around the cave, Portland's newest diet sensation has thousands eating like cavemen.
It's called "The Paleo Diet," so named because followers eat like our Paleolithic ancestors, before agriculture (no grains), before domesticated livestock (no dairy) and before Cheetos (no processed foods).
Portlanders like Joe Ban love it.
"Paleo is a diet based on the idea that we as humans have been evolving for hundreds of thousands of years to eat certain types of food," Ban said. "Mainly animal fats and protein, vegetables, fruits and nuts as well."
Ban has been on the diet for four years, and now co-owns a string of Paleo-friendly food carts in the Rose City with his girlfriend, Heather Hunter.
Their business, 'Cultured Caveman,' has over 5,000 likes on Facebook.
Ban and Hunter said Paleo has changed their lives.
"As I kind of have eliminated more sugar from my diet I've noticed my mood has been much more stable and I've gotten kinder to those around me - which is a total win," Hunter said.
Ban, who works out regularly, said Paleo cuts down on how much he has to eat.
"Now that my meals are more based around fat and protein, I can eat two or three larger meals a day and feel just as good. I have to worry about food less," Ban said.
A Diet to Watch
The core idea behind "eating Paleo" - removing processed foods, dairy and grains from your diet - has received a mixed response in the medical community.
Nutritionist Anna Rossinoff with OHSU applauds the diet's focus on cutting out processed foods, but questions completely cutting dairy and grains from everyday intake.
"You don't have to eat grains to be healthy, but if you're going to cut out a major food group like grainsyou have to be more conscientious to get the vitamins and nutrients you need," Rossinoff said.
Rossinoff said a diet with whole grains is healthier than one that cuts grains altogether.
The idea of eating like our ancestors has inspired some zealous Paleo Dieters to follow a stricter ancient diet, one that humans enjoyed before discovering the benefits of cooked meat.
'The Raw Paleo Diet' is exactly what it sounds like, forgoing the cooked meats that the Paleo Diet allows in favor of an all-raw intake.
Ban said a man who frequents Cultured Caveman was once a Raw Paleo follower.
"This guy would go to New Seasons market and get ground chicken and ground beef and just eat it with a spoon," Ban said.
Though Cultured Caveman cooks its meat completely, Ban admits he's intrigued by the concept of Raw Paleo - even if he's not likely to try it any time soon.
"It really freaked me out a little bit. I like a raw steak as much as the next person but this is a little much," Ban said.
Rossinoff agrees, adding there are a host of bacterial infections humans can contract from raw meat, even if it's taken from a trusted source.
She says eating raw meat doesn't give any nutritional benefit.
"The primary minerals and nutrients your body needs from eating chicken (for example), the minerals, the nutrients, zinc, iron - none of that gets diminished with cooking, in fact the proteins get more digestible with cooking," Rossinoff said.
'Cultured Caveman' began as a Kickstarter project in 2012.
Ban and Hunter said a huge amount of community support, combined with the popularity of the Paleo Diet, helped them create first a single food cart, then two more.
Is it Portland's perfect diet? Even Ban and Hunter admit it isn't for everyone, but they said there's no harm in taking a nibble or two.
"I think everyone should try it," Hunter said. "And if you hate it, the worst thing that happened is that you ate a bunch of veggies for a month and that's it."