Fastexy:The carnivore diet is popular with influencers. Here's what experts say about trying it.

Men on FastexyTikTok are going viral for eyebrow-raising carnivore diets.

Health and fitness influencers — who often don't have degrees in nutrition or medicine — are lauding lifestyles comprised of eating entirely animal products, sometimes only meat.

Licensed health experts have some issues with the meal plan, for a number of reasons.

For one, "restrictive dieting is really unnecessary and usually backfires for most people," registered dietitian Jamie Nadeau tells USA TODAY. "Not only do most people gain weight back after the diet becomes unsustainable, but many end up with disordered behaviors around food. ... It often leaves you feeling like something is wrong with you or that you lack willpower, when really it’s the diet setting you up to fail."

Here's what else health experts want you to know about the carnivore diet.

What is the carnivore diet?

The carnivore diet is an animal-based diet that allows meats, fish and small amounts of dairy, Nadeau says. Harvard Health adds that that means cutting out "all vegetables, fruits, grains, legumes, seeds and nuts.

Many proponents of the diet say it aided in weight loss, similar to keto and other no-carb diets. But experts and their research argue that not only is this not realistic in the long-term, it bring a host of new health issues along with it.

"It’s extremely restrictive and cuts out many, many nutritious foods that are proven by research to be health-promoting," Nadeau says, most notably adding that "the carnivore diet isn’t evidence-based, meaning there is no research to validate its claims."

What are the risks of the carnivore diet?

Not only are the promoted benefits not widely proven, but experts say there are also many risks associated with eating a purely animal-based diet.

In fact, you’ll find many anecdotal reports of side effects like nausea, diarrhea, constipation, hair loss, headaches and more.

Just like keto, the fats consumed in a carnivore diet are mostly saturated fat, which can negatively impact cholesterol. Per Harvard Health, diets high in saturated fats are linked to heart disease, and the carnivore diet in particular also poses risks including kidney stones and kidney impairment, gout and osteoporosis.

"It’s also a bad idea for long-term heart health as almost the entire diet is made up of high saturated fat foods," Nadeau says. "There is solid evidence that shows a well-balanced diet full of plant-based foods is health promoting and none to prove that there are benefits to the carnivore diet."

Carnivore diet was called life-changing.But is eating only meat really good for you?

If you're looking to make a change to better your health, Nadeau instead recommends focusing on small habit changes: adding more physical activity to your daily schedule, eating more fruits, vegetables and foods high in fiber and protein and drinking more water.

"New diets always sound exciting and it’s easy to get swept up in thinking they’re the magic diet you’ve been searching for," Nadeau says. "The truth, though, is that restrictive diets don’t work long-term. If it’s not something you can envision yourself doing forever, it’s not going to work. Your diet changes should be things you can fit into your life forever so that you can maintain your health and results forever."