- People who only eat meat say the diet boosts their mood, fitness, and weight loss.
- Some experts are skeptical about the anecdotal benefits because of a lack of long-term evidence to support them.
- Meat can be a rich source of nutrients, but cutting out all plants may have trade-offs for mental and physical health.
Amber O’Hearn stopped eating leafy greens and non starchy veggies 13 years ago after reading about carnivore diets on a Facebook group filled with carb-free advocates.
She intended to try it out for only a few weeks, but stuck with it after seeing dramatic benefits for her mental and physical health.
“I immediately started dropping weight and feeling better. My mood was really lifted,” O’Hearn told Insider. “I felt like everything I was eating was already healthy, which is why it was so surprising.”
People who follow the diet eat mostly animal products — no grains or vegetables, no processed foods, and no added sugars. Some dieters include dairy, honey, and fruit, while others are strictly meat, salt, and water.
While there’s little published evidence on the carnivore diet, advocates say they’ve lost weight after years of failed dieting, managed chronic health issues, and restored energy, according to a 2021 survey.
The diet is controversial, with concerns from some nutritionists and medical experts that it could spike cholesterol, endangering heart health. It may also deprive dieters of important plant-based nutrients like fiber and polyphenols, a lack of which may raise the risk of long-term illnesses like cancer.
“The carnivore diet is not what I would consider a healthy diet for the majority of people,” nutrition expert Layne Norton told Insider. “If you’re going to eat meat, I don’t necessarily think that’s a problem, but you definitely shouldn’t omit fruits, vegetables and fiber.”
Proponents, including some experts, say meat-heavy diets are a nutrient-dense alternative to typical American fare high in refined grains and sugar.
But some nutrition researchers are skeptical about alleged benefits, arguing anecdotal success stories are no substitute for rigorous science, and cutting out plants may do more harm than good.
Advocates say carnivore diets can help with a range of symptoms from mental health to auto-immune disorders. Some nutrition experts argue anecdotal evidence isn’t enough.
Meat-only eaters have self-reported improvements to their mental and neurological health, and said auto-immune symptoms subsided while following the diet. But according to Norton, there’s no evidence for that.
He said without rigorous research to back up personal success stories, alleged benefits of the carnivore diet aren’t convincing.
“I’m not saying people are lying about their experience or they aren’t having improvements, but probably more to do with factors other than some intrinsic magic to a meat-only diet,” he said.
A possible explanation for these experiences is that eating meat may address the root causes of some mental and physical health issues, Dr. Georgia Ede, a nutritional psychiatrist, said.
Symptoms of fatigue, mood swings, and more may be related to factors like nutritional deficiencies, or issues with the immune system, metabolism or digestion, Ede said.
For example, carnivore diets are virtually carb-free, which means they don’t spike blood sugar, perhaps helping to balance chemicals in the brain that regulate mood and cognitive function, according to Ede.
Carnivorous eating also works as an elimination diet by cutting out processed foods, Shawn Baker, a former orthopedic surgeon and one of the most high-profile carnivore advocates, said.
It’s not clear whether the anecdotal benefits of a carnivore diet are related to eating more meat or less of other foods, but both may play a role depending on what the diet is replacing, Ede said.
Amy Berger, a certified nutrition specialist, told Insider red meat has been “unfairly demonized and targeted.”
“It’s an extremely nutrient-rich food people have been eating for millennia,” she said.
A marathon runner said going carnivore — sometimes raw — improved his sleep and recovery after exercise
Jake Thomas, a Marine and marathon runner, said he made the carnivore diet a staple after trying it for 30 days in 2020.
After briefly experiencing brain fog, irritability, and headaches on the diet, Thomas said he didn’t want to stop — he was sleeping better, had more energy, and felt less sore after exercising.
“It’s like rocket fuel. Everything I’m consuming is giving to me,” he said.
A typical day of eating for Thomas includes a pound of rib eye, four eggs slurped raw, raw dairy, and chicken thighs, bacon, and beef liver.
Thomas also occasionally eats his steak or bacon raw, although eating raw meat, especially pork, can lead to serious disease and parasitic infection, according to the CDC. He said he’s willing to brave the risks since eating raw made him feel more able to absorb and connect with his food.
“It’s such an intimate way to eat. It feels like a holy experience,” he said.
Extreme variations of the diet, such as raw carnivore, come with specific risks. Cooking meat is an important safety precaution to reduce bacteria, according to the U.S. Department of Health.
Strictly cutting out plant foods may have unintended health consequences
Another concern of carnivore diets is eliminating fruits, vegetables, and fiber, which research strongly suggests may have protective effects against illnesses like cancer and
, Norton said.
“The overwhelming majority of evidence strongly suggests that fiber is not harmful and very likely beneficial,” he said. “I think meat is a great source of high quality protein, but I don’t think it should be your only food.”
Some people may be sensitive to certain plants or types of fiber, but you can learn to avoid them without cutting out all plants, Norton said.
“Most people could get the purported benefits of a carnivore diet by doing an elimination diet and get the benefits of some other foods,” he said.
Any diet taken to extremes also carries some risk of disordered eating, such as orthorexia, or fixation with “clean” eating, and food phobias, according to dietitians and nutritionists.
“I’ve had people terrified to eat carrots,” Berger said.
More research is needed to understand benefits and risks of the carnivore diet
A major caveat to carnivore diets is that current information comes from anecdotal experience. No clinical trials have yet studied how a carnivore diet could help or hinder health, though experiments are underway.
However, it’s difficult to do rigorous long-term studies on the health effects of any diet, so most of what we know about consequences is based on observational evidence.
Health experts in nutrition and cardiology say diets high in animal fats and low in plant nutrients may harm heart health in the long run by increasing the risk of heart disease and cancer, and raising LDL cholesterol.
“We have no evidence that this is a good idea,” Stanford professor John Ioannidis told Outside. “We have mostly indirect evidence that this is a bad idea.”
In general, nutrition experts recommend eating high-quality whole foods, animal or plant, and cutting back on highly processed foods. Beyond that, people can experiment (ideally with expert guidance) to find what works for them.
To make dietary changes, Berger said, trying an approach for up to 30 days to see how you feel is relatively low risk.
“People over complicate this. If you want to just eat meat, just eat meat,” she said. “You didn’t hear about it from your doctor, and it’s unconventional, but it should have a seat at the table.”