The Carnivore Diet Review

Does it Work?

There is no scientific evidence supporting the long-term effectiveness or safety of the Carnivore Diet. Some people have claimed to experience weight loss and improved health on this diet, but these claims are mostly anecdotal and not backed up by rigorous scientific studies. It is essential to approach any dietary regimen with caution and to consult a healthcare professional before making significant dietary changes.

Carnivore Review

Overview of the Carnivore Diet

The carnivore diet has gained considerable media attention thanks to its outspoken supporters who argue that it can cure depression and rheumatoid arthritis. However, there is no direct or indirect evidence to support these claims, and they are purely anecdotal. A Sample daily menu for someone following the carnivore diet includes eggs, bacon, sardines, turkey burger patty, strip steak, salmon, pork chops, scallops cooked in butter, a small glass of heavy cream, beef jerky, hard-boiled egg, and a small amount of cheddar cheese. This diet eliminates all plant foods.

In his 2019 book, The Carnivore Diet, Baker claims that phytochemicals, antioxidants, and fiber are unnecessary for our health, a claim that contradicts abundant research on the benefits of these plant-based nutrients. He also disputes established recommendations for vitamins and minerals. The diet's restrictions are based on some food beliefs, such as the claim that legumes and grains contain anti-nutrients such as phytates and lectins that interfere with the absorption of certain micronutrients, though they also provide health benefits. Additionally, it posits that all carbohydrate-containing foods are hazardous since the body converts them to "toxic" sugar. Modern science, however, does not support these claims.

Although some people may argue that the carnivore diet is a good choice, it lacks the strength of evidence, and is not balanced, affordable, or easy to follow. It is imperative to approach any dietary regimen with caution and to consult a health professional before making significant dietary changes. This Harvard Health Publication is meant to provide information and awareness about the carnivore diet and its potential implications on one's health.


The Carnivore diet is a highly restrictive diet although the concept of eating meat is simple that excludes all plant-based foods, it is not recommended due to the lack of scientific evidence supporting its health claims. Although weight loss claims are anecdotal, the diet poses significant health risks, especially for those with preexisting conditions.

The Carnivore Diet Approach

The carnivore diet is a dietary regimen that consists of eating exclusively animal products such as meat, poultry, fish, dairy, and water. That means no more fruit, vegetables, grains, starches, nuts and legumes because the diet dictates you only eat meat. The idea behind this diet is that our ancestors mainly subsisted on meat and fish, and high-carbohydrate diets are the root cause of modern chronic diseases. Proponents of the diet claim that by removing all plant-based foods from our diets, we can achieve optimal health, weight loss, and increased energy levels. However, there is no scientific evidence supporting these claims, and the long-term safety and effectiveness of this diet are not well-understood.

Food You Can Eat and Restrictions

The Atkins diet allows a range of foods, with specific allowances and restrictions depending on the phase.

Allowed Foods

  • Meat of all types
  • Poultry
  • Eggs
  • Lard
  • Bone marrow
  • Bone broth
  • Dairy foods that are high in fat and low in lactose (such as heavy cream, hard cheese, and butter)
  • Water

Foods to Avoid

  • Vegetables
  • Fruit
  • Grains
  • High-lactose dairy (milk, yogurt, soft cheeses)
  • Legumes
  • Nuts
  • Seeds
  • Alcohol
  • Sugar
  • Any beverages other than water

Carnivore Diet Risks

The carnivore diet is an extremely restrictive dietary regimen that eliminates entire food groups from one's diet, which can lead to several risks and consequences. On a carnivore diet, there are no parameters around when and how much you should eat. Instead, the diet revolves around approved animal foods. One significant risk of the carnivore diet is its low fiber content, which can cause constipation and other digestive issues. Furthermore, individuals with pre-existing health conditions, such as high blood pressure, high cholesterol, or a history of stroke or cardiovascular disease, should avoid the diet since the high intake of protein and fat can worsen these conditions. Given that the diet consists solely of animal foods, it can be high in saturated fat and cholesterol. 

Individuals with pre-existing health conditions, such as high blood pressure, high cholesterol, or a history of stroke or cardiovascular disease, should avoid the diet since the high intake of protein and fat can worsen these conditions.

The carnivore diet is high in saturated fats, which can elevate LDL or bad cholesterol levels and put individuals at risk of heart disease. Moreover, processed meats such as bacon and certain lunch meats are high in sodium and have been linked to certain types of cancer. A diet high in sodium can also cause kidney problems and high blood pressure. It is crucial to consult a healthcare professional before attempting any restrictive dietary regimen like the carnivore diet, as it may pose severe risks to your health.

Not All Carbs are Bad

Carbohydrates are not all created equal, and not all of them are bad for you. In their natural form, carbohydrates provide essential fuel for your body and can be loaded with fiber, vitamins, and minerals that are vital to good health. The best types of carbs are the ones that resemble their natural state the most and are not processed or refined. Some healthy options to consider include fruits like apples, pineapple, and strawberries, as well as vegetables like carrots, sweet potatoes, and beets. Whole grains such as quinoa and whole wheat bread are also excellent sources of healthy carbohydrates.

On the other hand, simple carbohydrates like sugary candies, cakes, and pies are the ones to avoid. These types of carbs are often full of preservatives, white sugar, and flour, and are notorious for causing inflammation and weight gain, especially around your middle. Additionally, simple carbs are known contributors to many adverse health conditions, including type 2 diabetes, obesity, and high blood pressure. While cutting out simple carbs from your diet may lead to weight loss and better glucose level control, it is unnecessary to eliminate all carbs for good health.

In fact, completely omitting carbohydrates from your diet can cause real damage to your body. It is crucial to understand the difference between good and bad carbohydrates and incorporate healthy carbohydrates into your diet for optimal health.

The Latest Research

Heart Disease

It is challenging to find many health professionals who believe that a diet devoid of whole grains or fruits and with limited vegetables is beneficial for heart health. Evidence suggests that high-protein diets may increase the risk of heart disease and congestive heart failure.

In 2018, researchers analyzed data from approximately 2,400 men aged 42 to 60, collected between 1984 and 1989. These men were asked to record their food intake for four days and were followed for 22 years. During this period, 334 of them developed heart failure. The higher their protein intake, the greater their risk of heart failure. Men who consumed the most animal protein had a 43% higher risk of heart failure than those who consumed the least. Those who consumed the most dairy protein had a 49% higher risk. However, individuals with the most plant protein only had a 17% higher chance. Protein from eggs and fish was not associated with an increased risk. In a 2020 review of 12 randomized studies, a low-carbohydrate diet was linked to decreased triglycerides, blood pressure, and total cholesterol (although LDL cholesterol increased, and fasting glucose did not change significantly). However, weight loss often reduces blood lipids, blood pressure, and glucose levels that contribute to developing cardiac conditions. This makes it difficult to accurately determine which improvements in heart health are due to the weight loss itself or the diet responsible for the weight loss.

Curing SIBO

Proponents of the carnivore diet suggest that it can improve gut health and cure small intestinal bacterial overgrowth (SIBO), which causes bloating, constipation, diarrhea, and other gastrointestinal issues. While a small study found that participants who followed a zero-carb, zero-fiber carnivore diet for four weeks tested negative for SIBO, another study found that switching to a zero-carb, carnivore diet caused significant detrimental changes to the gut microbiome. Additionally, a study from 2021 compared the changes in the microbiome after four weeks on a vegan diet versus a meat-heavy diet and found that the results varied based on individual participants. While some people with irritable bowel syndrome or inflammatory bowel disease may see a decline in symptoms after adopting the carnivore diet, the diet's restrictive nature poses several health risks, and there is no scientific evidence supporting its health claims.

Cancer Risk

Eliminating all food groups except for one carries several health risks, including an increased risk of cancer. Plant-based diets have been shown to greatly reduce the risk of various cancer types, cardiovascular disease, and diabetes. On the other hand, a diet heavy in red and processed meats, like the carnivore diet, can increase the risk of stomach and colorectal cancer. The high intake of red meat, which is a leading carcinogen, is a significant concern for Harvard MD Aaron Bernstein, who does not recommend this diet due to the increased risk of colon or rectal cancer.

Elevated Cholesterol

The carnivore diet promotes foods that are high in saturated fat and cholesterol, which can have harmful effects on heart health. Experts note that the diet eliminates healthy unsaturated fats from sources like avocados and nuts, which protect brain and heart health. Studies have shown that consuming excessive amounts of saturated fat and dietary cholesterol can increase cholesterol levels, clog arteries, and increase the risk of heart disease. Although these foods can be included in a balanced diet, consuming them in moderation is essential to avoid compromising health. Elevated cholesterol levels can lead to atherosclerosis, heart attack, and stroke, making the carnivore diet unsuitable for individuals with a personal or family history of cardiovascular disease and hyperlipidemia. As a result, a balanced diet consisting of all food groups is a better option than the restrictive carnivore diet.


  1. Brehm, B. J., Seeley, R. J., Daniels, S. R., & D'Alessio, D. A. (2003). A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women. The Journal of Clinical Endocrinology & Metabolism, 88(4), 1617-1623. Link:
  2. Foster, G. D., Wyatt, H. R., Hill, J. O., McGuckin, B. G., Brill, C., Mohammed, B. S., ... & Klein, S. (2003). A randomized trial of a low-carbohydrate diet for obesity. New England Journal of Medicine, 348(21), 2082-2090. Link:
  3. Shai, I., Schwarzfuchs, D., Henkin, Y., Shahar, D. R., Witkow, S., Greenberg, I., ... & Tangi-Rozental, O. (2008). Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. New England Journal of Medicine, 359(3), 229-241. Link:
  4. Volek, J. S., Sharman, M. J., Gómez, A. L., Judelson, D. A., Rubin, M. R., Watson, G., ... & Kraemer, W. J. (2004). Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Nutrition & Metabolism, 1(1), 13. Link:

Rating and Review

William H. McDaniel, MD

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School.

Carnivore Diet: A Good Choice?
  • Scientific Evidence
  • Weight Loss
  • Health Impact
  • Balance
  • Affordability
  • Ease and Sustainability


The Carnivore diet is an extremely restrictive dietary regimen that involves consuming only high-fat animal products while excluding all forms of plant-based foods. However, this diet is not recommended as there is no scientific evidence supporting its various health claims. The weight loss claims associated with this diet are mostly anecdotal, and the diet poses significant health risks, especially for individuals with preexisting conditions. Additionally, this diet is challenging to sustain due to its restrictiveness, and the side effects can be uncomfortable.



  • The carnivore diet eliminates ultra-processed foods that are high in sugar and other refined carbohydrates, which can contribute to weight gain and other health problems.


  • The carnivore diet is high in saturated fat and sodium, which can increase the risk of heart disease and other health problems.
  • The diet lacks fiber, beneficial phytochemicals, and many essential vitamins and minerals, including those necessary for pregnant women.
  • It is high in cholesterol, which can be problematic for individuals who are cholesterol hyper-responders, experiencing a dramatic rise in blood cholesterol when dietary cholesterol increases.
  • There is no scientific research to support the various health claims associated with the diet.
  • A meat-based diet has an adverse environmental impact, as animals require more water, energy, and land to grow than plants, and they produce more greenhouse gases.

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