It’s the ultimate throwback: Eat like a caveman. The proliferation of the Paleo diet has been seemingly overnight, but the concept of it—beyond the obvious beginning in the Stone Age—first came about in the 70s. A 2002 book by Loren Cordain codified the rules of it, but it took a decade for the idea to officially become a fad.

Websites, cookbooks, and blogs dedicated to the rules of the regimen popped up, and hardcore followers emerged. They stick to basic tenets: First man was a hunter-gatherer, thus the human body is made to consume the items he had access to: protein, fruits and vegetables, and healthy fats. There’s no room for dairy products, processed items, sugar, and grains.

The idea has been met with skepticism. “I really have more of a problem with the premise of it,” explains Lisa Cimperman, a dietitian and spokesperson for the Academy of Nutrition and Dietetics. “Cavemen had a lifespan of 30 years. Personally I don’t want to go hunt mammoth.”

However, those who have tried what was considered a passing trend have found it can be turned into a way of life.

When Joanna Beituni moved to the D.C. area three years ago, her new roommate kept a Paleo kitchen. She didn’t want to disturb the rules of the house, so she started eating the same way to test it out.

“I’ve had struggles with diets and finding something that works with keeping weight off without restricting my life too much,” she says. At first, the protein and vegetable-rich menu was also an effort until Beituni found the right balance. Then she felt a transformation; she lost 50 pounds in that first year and found that consuming the prescribed foods was a cinch.

“You’re not really doing anything different,” she continues. “You’re eating real food. Everything I needed I had access to. To me it’s not a fad; it’s more of a lifestyle.”

For Fatima Hatia, a physician from Bloomington, Illinois, the so-called rage was a godsend. After being diagnosed with multiple sclerosis, she began researching how she could supplement medical care. Dr. Terry Wahls did a TED Talk on the importance of nutrition with the disease, which piqued Hatia’s interest.

Vandana Sheth, a Los Angeles-based dietitian nutritionist and also a spokesman for the Academy of Nutrition and Dietetics, agrees that the Paleo lifestyle has proven to be anti-inflammatory, which is a major part of multiple sclerosis.

Hatia decided to try a change in her eating habits to see if it made a difference in her symptoms. “I just had to cut out the rice and the pasta and the bread,” she expands. She experimented with almond flour, coconut flour, and even bought an ice cream maker, where she churned out treats using coconut milk.

“It changed my life,” she rejoices. “I felt like when I was diagnosed it was the end of the world. I love playing sports, and I thought I was going to be wheelchair-bound. Now I feel really good, high in energy.”

Cimperman and Sheth contend that if any client comes to them wanting to incorporate a specialized way of eating, they certainly will work around it. Although they would recommend a basic plan that includes fruits and vegetables, lean protein, low-fat dairy, and whole grains, they agree that Paleo or gluten-free, for example, may be what keeps someone motivated enough to stick to a healthier routine.

Of course, many have no choice in cutting out gluten; those with celiac disease have to eliminate the trigger found in wheat, rye, and barley from their bodies.

That was Ambreen Zaki’s task when her seven-year-old son and three-year-old daughter were diagnosed. At first, she kept up her previous foods for herself and her husband, but maintaining a completely contaminant-free kitchen—including separate food storage containers and cooking utensils—became too much hassle. Her children’s health was also not responding, so she decided her whole family would avoid gluten.

Isabelle Othman was also diagnosed a decade ago, when options weren’t nearly as palatable. Now, there are more options available in stores, but Othman initially dealt with bread alternatives that were dry and crumbly. “That is actually what pushed me to learn about gluten-free baking,” she expounds. “Now, I can take nearly any gluten recipe and convert it to a gluten-free one.”

Othman took that passion for testing recipes and opened her own online bakery in South Korea, where she currently lives. At first she wasn’t sure how the locals would react, but she’s built a strong customer base and hopes to have a storefront soon.

Zaki, who lives in Chicago, also experimented with recipes that could accommodate some South Asian cooking and found which substitutes tasted good and which ones to avoid. She also prepares all the meals for her children, including chicken nuggets from scratch with alternative breading.

“Since we’ve been doing it since last year, I’ve noticed there’s a lot more awareness in people now,” she says. Because so many products these days do tout themselves as being gluten-free to accommodate those who can’t have it, the idea has become a bit of a trend.

Aatifa Ahmed of Bloomington, Illinois, took it on because she noticed a drastic change in a friend’s daughter who everyone thought was just an introvert. When her friend’s daughter gave up the grains that irritated her system, she was no longer tired. Ahmed wanted to take advantage of that surge in energy herself.

She was strictly gluten-free for a few months and now avoids it at breakfast. “I just felt more energized and felt like I was doing more clean eating.”

Cimperman sees this movement toward Paleo and gluten-free as a resurgence of the low-carb craze from the early 2000s and points out research has shown that it’s not actually grains that cause bowel issues for those who don’t suffer from celiac—it’s specific fermentable carbohydrates. “Carbohydrates have certainly gotten a bad rap for a number of years,” she laments. “Carbs that are high in refined grains and high sugar are certainly poor choices. Carbohydrates that are sources of whole grains and fiber are beneficial.”

Sheth agrees that there’s no one-size-fits-all regimen for anyone but that consumers are leaning more toward staying away from processed items, which is always a plus.

Most who are on a specialty diet will also spend much of their time researching sources of nourishment and what they’re putting into their bodies, and that definitely is what leads many to try another specialty diet: veganism.

For Parvez Ahmed, located in the Bay Area, it was health concerns first and then a cognizance that he wanted to have a positive environmental impact with his choices. One documentary, Forks Over Knives, which explores the connection between food and chronic diseases, led him further on the path to becoming a vegan.

“I became growing increasingly concerned about pesticides, steroids, [. . .] antibiotics,” he elucidates. He also feels his choice falls within the realm of Islam. Although he concedes it’s debatable whether it was a matter of availability, the Prophet Muhammad (Peace Be Upon Him) ate meat sparingly.

While he’s added fish and some dairy back into his life, Ahmed doesn’t see avoidance of meat products as a passing fancy, and he feels the industry around him illustrates that. There are plenty of books, online recipes, and stores that cater to those who choose not to eat living beings. “I think there’s certainly not a paucity of that anymore like there used to be.”

That also was a surprising factor for Navaal Mahdi, a Baltimore-area college student, when she decided to adopt veganism. “It’s so great because of social media,” she contends. “I’m always on Instagram, and I follow a bunch of vegan accounts.” When she finds a recipe that looks appetizing and different, she tries to make it on her own over the weekend.

Restaurants are also more accommodating to any needs and will often alter menu items if a customer requests it.

Because of the changes she’s seen in herself—her mood is better, she’s become more patient, she’s been able to maintain a healthy weight, which was always an issue previously—Mahdi thinks she’s found her new lifestyle.

Experts do contend that even with ethics-based decisions to avoid eggs, dairy, and meat, it’s still important to keep in mind that balance is key. It’s entirely possible to be an unhealthy vegan or to lose control on a Paleo diet.

“Even with these fads and trends, they can be done in a healthy or nutritionally complete way or can be done in a way that leaves holes,” Cimperman says. “I think the bottom line is the specific diet you choose to follow is not as important as the types of foods you choose to eat.”

Nadia Malik holds a degree in journalism and is a former reporter for a Chicago-area newspaper. She has written for websites and publications and has also worked for several non-profit organizations.