This piece originally aired on Nov. 7, 2014.
What began as the paleo diet has exploded into a full caveman movement.
Supporters believe eating, exercising and sleeping like our ancient ancestors will help us lose weight and feel healthier, reports CBS News correspondent John Blackstone.
At popular CrossFit gyms, the emphasis is on getting more exercise with less equipment -- workouts that can be done anywhere.
Imagine CrossFit in the age of the caveman: the website movnat.com calls it the workout the world forgot, exercising much like our predecessors in the Paleolithic era might have done.
Robb Wolf, best-selling author of "The Paleo Solution," runs a gym in Northern California.
"The point is it's fun and effective," he said. "It's usually in a group format so you get a little bit of that tribe, that community."
Henry Fong and Michelle Tam have always been interested in fitness, their garage is now a paleo exercise room for the whole family, but they were not impressed when they first heard about paleo five years ago.
"I started downloading articles from the web and showing them to Michelle and we both laughed over them and thought they were ridiculous," Fong said.
But then Fong gave the paleo lifestyle a try.
"And so when he started telling me, 'oh I don't know if whole grains are the best thing for us to eat, and maybe saturated fat isn't such a bad idea, and red meat might actually be good for you,' I thought he was bananas," Tam said.
Tam, a pharmacist by profession, had no intention of adopting caveman cuisine, but noticed the change in her husband.
"He just felt so much better, and he had all this energy and he was getting a six-pack and so I decided to give it a try," she said.
"As soon as she converted to paleo, out went all of the junk food in the house," Fong said, "and so I have no choice."
Tam began posting paleo recipes online. Her blog now averages 100,000 views a day. With a best-selling cookbook and an app, she's been called the "Martha Stewart of paleo."
"I put up recipes that are paleo-friendly," Tam said. "To me, the caveman is just a mascot. But I think it's important to learn from our past and so it's just kind of finding out what works for you."
The caveman diet consists largely of grass-fed meat, wild fish, fresh fruit and vegetables, eggs, seeds and nuts. Processed foods, sugar, grains and dairy are to be avoided.
"Where the paleo diet kind of comes into conflict is recommending lots of red meat," Director of UCLA's Center for Human Nutrition Dr. David Heber said.
He pointed out you really can't replicate a stone age diet.
"Things like strawberries, blueberries, and pistachios and almonds, all didn't exist in the Paleolithic times," he explained. "Things like Greek yogurt, that's a great source of protein and low in fat. And so I think today's diet is actually superior to the Paleolithic diet."
Yet the primal lifestyle has spawned a mini-industry, from beauty products to paleo retreats, even foods like paleo pancakes and cornflakes -- perfect for cave children.
"When they're in my house, I feed them my food," Tam said. "But when they're out in the wild, I let them make their own decisions."
She realized the caveman nature of her explanation.
"When out in the wild," she laughed. "That's as paleo as I get. I let them make their own decisions."
For the caveman, sunrise marked the start of day. Sunset, the time to rest. To get closer to that natural sleep pattern Tam wears amber goggles while using electronic devices at night, reducing the blue-spectrum light that can disrupt sleep.
While the health benefits of a paleo lifestyle are unproven, bursts of strong, natural movements clearly helped man survive the stone age.
"If something were to happen, I could pick up my kids and run out of the house," Tam assured. "If something were to happen to Henry, I could probably dead-lift him as well."
She said she feels stronger and better.
"That's probably why I have this website, is because I've become an evangelist for it," Tam said.
It should be noted that the average lifespan in the Paleolithic era was about 35 years. But back then, of course, just surviving was a lot more challenging than it is for modern paleos.