Humans have evolved the ability to digest all manner of food items, from fruits and vegetables to animal products. Debate continues about what constitutes the best ratio of various types of food to support optimal human health, but a new entrant into the diet scene suggests that all plants are suspect and we should embrace a meat-only diet for improved physical well-being.
The carnivore diet “consists of consuming only animal products,” says New York City-based registered dietitian Jamie Feit of Jamie Feit Nutrition LLC. “It’s basically eating eggs and bacon for breakfast, a steak for lunch and cheeseburger and bacon for dinner. There’s basically no gray area and no leeway for adding additional food groups.”
Dr. Paul Saladino, an integrative medicine and nutritional biochemistry practitioner in private practice in San Diego and author of “The Carnivore Code: Unlocking the Secrets to Optimal Health by Returning to our Ancestral Diet,” is a staunch proponent of the carnivore diet. He says going carnivore is the solution to a range of health issues currently plaguing humankind. Plants, he says, simply aren’t cutting it.
“If you look at the incidence of chronic disease, no one can deny that in the last 70 years, we’ve become abysmally unhealthy,” Saladino says. “Rates of obesity and overweight are 70% of the U.S. population. Diabetes has gone from 0.9% or 1% to 13% or 14%. And that’s just diagnosed diabetes, not pre-diabetes or metabolic syndrome. Chronic disease now impacts 40% of the population. Fifty or 60 years ago it was 10% or 15%. So the question is, what the heck happened?”
He continues, noting that we’re drinking less alcohol, smoking less and exercising more, and yet we still get sicker. “Unhealthy behaviors have gone way down. And if you look at the number of people who are eating ‘healthfully,’ that’s gone way up. But that’s just according to the U.S. dietary guidelines.”
What’s happening is a good question, and according to Saladino, the answer is that “we’re doing some things that are incompatible with our genetics and evolutionary history that are causing us to get sick.” Namely, eating plants. “Having more vegetables and eating less red meat, we’re getting sicker and sicker.”
He notes that red meat bears the blame for many ailments and chronic diseases, and he thinks this is backward. Plants, he says, are varying levels of toxic to humans, hence why so many of them are poisonous and even some of the ones we can eat, such as beans, must first be must be carefully prepared and cooked to remove toxic proteins. “It’s not a question of if plants are toxic, it’s a question of how toxic any one plant is and how well any individual or animal can detoxify what’s in there,” he says.
By contrast, he notes that “animals don’t have toxins in their body with a few rare exceptions of a small frog in the Amazon and puffer fish liver. But generally speaking, 99.9% of animal organs are all edible by humans. And in fact, it’s incredibly nutritious food and basically what we’ve been thriving on for two to four million years.”
An All Meat Diet
For meat eaters who are interested in trying the carnivore approach to eating, you’ll have to cut out all plant foods. Yes, really. The goal is to eliminate all carbohydrates, and Saladino says that, save for the odd berry or other seasonal fruit our carnivore ancestors would pick up while hunting game, plants are not on the menu.
“It works as an elimination diet by slowly reducing intake of carbohydrates and plant-based food items and increasing intake of animal protein,” Zammit explains. “Oftentimes on an elimination diet, food items may be slowly reintroduced, but that’s not the case here. The ultimate goal is 100% intake of animal-based protein.”
Followers of the diet are instructed to eat any kind of meat and meat product, from fatty cuts of beef, lamb, pork and organ meats, as well as poultry, fish, eggs and dairy products.
A typical carnivore diet meal plan
A typical menu for a day on the carnivore diet can be:
— Breakfast: a 4-ounce ribeye, two eggs and bacon cooked in butter.
— Lunch: 3 ounces of salmon and 6 ounces of shrimp.
— Dinner: 2 ounces of liver and 8 ounces of filet for dinner.
“There’s no flexibility for a bun on your burger or a piece of fruit for dessert,” Zammit says.
The reason for this very restrictive emphasis on animal protein is simple, Saladino explains. “Animal meat and organs are the most nutrient-rich and bioavailable foods on the planet. They’ve been incredibly vilified for the last 60 years, but they’re an integral part of every healthy human diet.”
It’s true that organ meats are highly nutritious, being rich sources of B vitamins, several minerals, including iron, magnesium, zinc and fat-soluble vitamins including vitamins A, D, E and K. Organ meat and animal meat in general contain high levels of protein. And it’s true that our hunter-gatherer ancestors ate every part of the animals they hunted, nose to tail.
The idea with this approach is to be as animal-based as possible, as opposed to plant-based. However, plant-based diets such as the Mediterranean diet have long been favored by many dietitians and doctors as the healthiest and most sustainable way for humans to eat for longevity and wellness. The carnivore diet turns that conventional and well-established advice on its head.
[READ: The Keto Diet and Diabetes.]
Saladino claims that the carnivore diet can be the source of healing for virtually any autoimmune or chronic disease you might be experiencing, from depression and rheumatoid arthritis to diabetes, acne and obesity. There is limited or mostly anecdotal evidence for these claims.
A few of the commonly cited improvements that proponents associate with the carnivore diet include:
For example, one particular aspect of health that proponents of the carnivore diet often cite is an improvement in gut health. A common condition called SIBO often comes up in discussions of how the carnivore diet may impact the health of the gut microbiome. Proponents suggest that SIBO, or small intestinal bacterial overgrowth, which occurs when an excessive number of bacteria take up residence in the small intestine and cause bloating, constipation, diarrhea and other GI problems, can be cured by moving to a zero-carb diet like the carnivore diet.
In one very small, six-person study (that has not been peer reviewed or validated) found that five participants who followed a zero-carb, zero-fiber carnivore diet for at least four weeks tested negative for SIBO at the end of the observation period.
SIBO is often treated using broad-spectrum antibiotics, but proponents of the carnivore diet say this is unnecessary, and in fact, while antibiotics may clear up symptoms for a time, they often return within three to nine months. The concept here is that because the bacteria that cause SIBO need carbohydrates to thrive, starving them of this fuel source can wipe them out entirely from your gut.
In contrast, another small study published in the journal Nature in 2014 found that in just five days, participants who switched to a zero-carb, carnivore diet experienced significant detrimental changes to the gut microbiome, including a dramatic increase in strains of bacteria in the gut that cause inflammation and have been linked with Crohn’s disease and ulcerative colitis.
Zammit also notes that for some people with irritable bowel syndrome or inflammatory bowel disease, symptoms such as bloating and flatulence may also decline because you’ll be consuming far fewer FODMAPs, a type of carbohydrate that can cause gastrointestinal distress in some people.
Rapid Weight Loss
The all meat diet may result in weight loss because it’s high in fat. High-fat foods “promote meal satiety,” meaning that “you’ll feel fuller longer,” Zammit says. “Feeling satiated from consuming these food items can help reduce your caloric intake, as you won’t feel as hungry, likely leading to weight loss.”
There’s also some evidence that suggests excessive sugar intake can alter brain chemistry, which could contribute to the development of depression. Cutting back on sugar and processed carbs may improve mood, as has been observed with the keto diet in some studies. As an extreme form of keto, the carnivore diet, it can be argued, might also confer some mood-boosting benefits.
Better Glucose Control
Reducing your intake of carbohydrates may also help with blood glucose control, which may be helpful for people with diabetes. Some studies have also noted that the keto diet can reduce inflammation in the brain and body, which may also help with diabetes and other chronic medical conditions.
Results from a social media-based survey of people who had followed the carnivore diet for at least six months were published in the December 2021 issue of Current Developments in Nutrition. The survey found that participants with diabetes reported benefits related to diabetes and insulin resistance, with 74% saying the condition had “resolved” and 24% saying it was “improved.” The survey authors noted that “all respondents with diabetes discontinued noninsulin injection agents, 84% discontinued oral medications and 92% of participants with Type 2 diabetes mellitus discontinued insulin.”
While such results may seem overwhelmingly positive, it’s worth keeping in mind that surveys such as this rely on self-reporting and are not considered the gold-standard for scientific studies. Zammit cautions against confusing anecdotal support with scientific understanding. “This diet demonizes plant-based foods, such as fruits, vegetables, whole grains, beans, lentils, nuts and seeds, while promoting claims of improving fatigue, digestion and autoimmune diseases. These claims are not based on sound science, but rather anecdotal reports.”
Shaky health claims are one thing, but risks to health stemming from this way of eating are another. And most registered dietitians strongly discourage adoption of the carnivore diet.
“Frankly, this is not a healthy diet,” says Antonette Hardie, a registered dietitian with the Ohio State University Wexner Medical Center in Columbus. She cites several health risks associated with this diet including:
Zammit agrees that eliminating all food groups from your diet except one is not a risk-free endeavor. “There’s a lot to unfold here. But since I’m an oncology dietitian, let’s start with cancer risk.”
It’s long been established that plant-based diets may help ward off cancer. “We have strong evidence from several meta-analytical studies that demonstrate a plant-based diet can greatly reduce your risk of several cancer types, as well as other disease states, including cardiovascular disease and diabetes,” Zammit says.
Similarly, “it’s well-known that a diet heavy in red and processed meats can increase risk of stomach and colorectal cancer. We also know that a diet rich in saturated fat can increase risk of liver cancer,” Zammit explains.
Feit says the carnivore diet “is definitely a fad diet. Although it may have proposed benefits, it’s important to realize that this can never be considered a healthy diet. As stated by the American Heart Association, saturated fats need to be replaced by unsaturated fats in order to decrease heart disease, which is a leading cause of death. A diet consisting of all food groups is always a better way to go.”
Elevated cholesterol levels can lead to atherosclerosis, heart attack and stroke, and because of this, “if you have a personal or family history of cardiovascular disease and hyperlipidemia, the carnivore diet is not for you,” Zammit says.
Non-Alcoholic Fatty Liver Disease
Another potential concern with the carnivore diet is the risk of developing non-alcoholic fatty liver disease, “which is caused by the accumulation of saturated fat. This isn’t always reversible by changing your diet,” Zammit says. “When we have this buildup of saturated fat, it can cause inflammation of the liver, increasing the risk of liver cancer. A 2022 study published in the BMC Gastroenterology Journal found that diets that are heavy in red meat, sweets and processed oils increase risk for NAFLD.
Chronic Kidney Disease
The diet is also a poor choice for people with chronic kidney disease, even if they aren’t on dialysis. “With chronic kidney disease, you’re instructed to actually limit your protein intake,” she explains.
“The average protein needs of a healthy individual are 40 to 65 grams per day. When you have CKD, your kidneys no longer have the ability to remove protein wastes, which will then buildup in the blood and can cause a whole host of unpleasant symptoms, including nausea and vomiting, decreased appetite and weakness,” Zammit says.
Because the carnivore diet is bereft of all plant matter, it contains virtually no fiber. “Due to the lack of fiber, most people will end up with constipation,” Zammit says.
For his part, Saladino says humans don’t need fiber, and he calls it “one of the greatest cons ever foisted upon humans.” He says we don’t need fiber to digest animal products, and it causes more GI distress than it alleviates.
Malnourishment and Nutrient Deficiencies
“There’s also an increased risk of malnourishment, since you would no longer be consuming a balanced diet,” Zammit says. In particular, “vitamin C would be lacking, increasing risk of scurvy,” a disease that was common among sailors in the 18th century and causes swollen and bleeding gums, anemia, loss of teeth, weakness and poor healing of wounds. Scurvy can be deadly.
“In addition to all the medical and nutritional issues one may encounter on a carnivore diet, there’s also the psychological aspect of following a restrictive diet,” that you need to consider before you adopt this approach to nutrition, Zammit says.
“Following any restrictive diet can often lead to loneliness and social isolation. It can build distrust with yourself, disconnecting the relationship you have with your body and food. All this can affect your quality of life in a negative way, especially if following long term.”
As such, if you have a history of eating disorders, you’d be well advised to avoid this diet.
Lastly, if you’re undertaking the carnivore diet in an effort to lose weight, be aware that rebound weight gain can be an issue when you inevitably tire of this limited diet and begin adding back other foods. “With such a restrictive diet, you are prone to gain weight back and then some,” Hardie says.
How Much Does a Meat-Based Diet Cost?
Typically, meat products cost more than plant-based foods, and as such, “you may have to shell out more money than you realize to follow this diet,” Zammit says. “Although you won’t be spending money on the food items you used to include, you’ll make up for it and then some by having to purchase animal protein for all your meals.”
This cost is compounded by the fact that the diet encourages only using “grass-fed and ethically-sourced protein, which is very expensive, and not everyone has the privilege to obtain, depending on their neighborhood and socioeconomic status,” she says.
Carnivore Diet: Bottom Line
“Keep in mind, that when it comes to your overall health, diet is just one piece of the puzzle,” Zammit says. “Genetics, age and gender play a huge role in how your body reacts to certain food items or diets, and this isn’t something we can change.”
She also warns about being careful when comparing yourself to other people. “The human body is incredibly complex. There are no ‘bad’ foods, just bad overall diets. Behavior and lifestyle modification are still the best predictors of your health and happiness. At the end of the day, nourish your body based on your individual needs and preferences.”
She also recommends that if you’re thinking of beginning a particular diet, “please contact your local registered dietitian to help educate and guide you.”
If you’re looking for a healthy way of eating, Hardie notes that “there is so much more research out there that promotes a plant-based diet or Mediterranean diet vs. any other fad diet. The carnivore diet is just another fad diet that isn’t sustainable over time and can lead to several chronic illnesses such as high cholesterol and heart disease.”
For his part, Saladino, who is a devout follower of the carnivore diet, says he’s never felt better since adopting this lifestyle, and he encourages those who feel the need to make some changes to check it out.
“If you’re kicking ass in every way, shape and form, then don’t change a thing. But if you’re looking to improve body composition, libido, emotional stability, mental clarity, autoimmunity, inflammation, chronic disease, I’m so excited to offer these ideas as a tool for people who might not have considered them because we’re so stuck in this rigid paradigm around plants versus animals. It’s a diet for every homo sapiens person that isn’t thriving.”
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Carnivore Diet Review: Benefits, Risks, What to Expect originally appeared on usnews.com
Update 04/22/22: This story was previously published and has been updated with new information.