The carnivore diet, a highly restrictive eating pattern that eliminates all plant foods, has gained popularity for its potential benefits. However, the question arises: what happens when you introduce vegetables into this meat-centric regimen? This article explores the potential benefits and drawbacks of adding vegetables to a carnivore diet, providing a balanced perspective on this dietary modification.
Understanding the Carnivore Diet
The carnivore diet, in its purest form, is an extreme elimination approach that removes all plant foods. This means no exceptions for "healthy" vegetables or fruits. The diet consists entirely of meat and animal products, excluding all other foods. Specifically, someone on the carnivore diet can eat meat (beef, chicken, turkey, lamb, pork, etc.), organ meats (liver, kidney, sweatbread, tripe, heart, brain), fish (salmon, mackerel, sardines, crab, lobster, tilapia, herring, etc.), other animal products (eggs, lard, bone marrow, bone broth, etc.), and low-lactose dairy (in small amounts): heavy cream, hard cheese, butter, etc. According to some proponents of the diet, salt, pepper, and seasonings with no carbs are allowed. In addition, some people choose to eat yogurt, milk, and soft cheese, but these foods are typically not included due to their carb contents.
Restricted foods include vegetables (broccoli, cauliflower, potatoes, green beans, peppers, etc.), fruits (apples, berries, bananas, kiwi, oranges, etc.), high-lactose dairy (milk, yogurt, soft cheese, etc.), legumes (beans, lentils, etc.), nuts and seeds (almonds, pumpkin seeds, sunflower seeds, pistachios, etc.), grains (rice, wheat, bread, quinoa, pasta, etc.), alcohol (beer, wine, liquor, etc.), sugars (table sugar, maple syrup, brown sugar, etc.), beverages other than water (soda, coffee, tea, fruit juice, etc.). While some people incorporate some of these foods, a strict carnivore diet does not permit them.
The carnivore diet stems from the controversial belief that human ancestral populations ate mostly meat and fish and that high-carb diets are to blame for today’s high rates of chronic disease. Other popular low-carb diets, like the keto and paleo diets, limit but don’t exclude carb intake. However, the carnivore diet aims for zero carbs.
Potential Benefits of the Carnivore Diet
Some individuals report noticeable improvements on the carnivore diet. The carnivore diet claims to promote weight loss. Its other supposed benefits are for improving heart health, autoimmune issues, blood sugar control, and mood. Yet Baker only links to “success stories,” not medical research, to confirm these benefits.
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Weight Loss
Certain aspects of the carnivore diet may lead to weight loss. Specifically, some studies have shown that high-protein and low-carb diets can promote weight loss. This is mostly because protein, as well as fat, can help you feel more full after meals, which may lead to reduced calorie intake and subsequent weight loss. Protein can also increase your metabolic rate, helping you burn more calories. Therefore, following the carnivore diet would likely cause you to feel fuller and eat fewer calories overall - at least in the short term.
One 3-month study in 132 adults with excess weight or obesity compared the weight loss effects of 4 energy-restricted diets containing varying amounts of carbs and protein. Those who ate high-protein diets with 0.4-0.6 grams of protein per pound (0.9-1.3 grams per kilogram) of body weight per day lost significantly more weight and fat mass than those who ate 0.2-0.4 grams of protein per pound (0.5-0.9 grams per kilogram) of body weight per day. Other studies show similar results, suggesting that increasing protein and dietary fat intake may lead to weight loss and help reduce the amount of weight regained over time.
Cognitive Function
Diet plays a key role in cognitive performance, especially as we age. According to research published in Frontiers in Public Health, protein intake, especially from animal sources such as meat and eggs, has been positively linked to cognitive functions, including memory, attention, and verbal fluency. This supports the idea that protein is essential for brain health and may help prevent cognitive decline in older adults.
Stable Energy Levels
A carnivorous diet supports daily energy needs primarily through its high fat content, which serves as the body’s primary fuel source, especially in the absence of carbohydrates. Protein-rich animal foods also play a crucial role in preserving lean muscle mass. This is important as muscle tissue contains the highest concentration of mitochondria, which are cellular energy-producing organelles, helping support sustained energy throughout the day. Increased protein intake may boost the calories your body burns by supporting lean muscle mass, which helps maintain a healthy resting metabolism.
Elimination of Processed Carbohydrates
Since the carnivore diet excludes carbs, it eliminates cookies, cakes, candy, sodas, pastries, and similar high-carb foods. These foods are low in beneficial nutrients and often high in calories. Thus, they should be limited in a healthy, balanced diet. High-sugar foods can also be problematic for people with diabetes, as they can spike blood sugar levels. In fact, limiting refined carbs and sugary foods is often recommended to control diabetes. Due to the removal of highly processed carbohydrates in the carnivore diet, you might see some early benefits such as improved blood pressure, reduced belly fat, and improved cardiovascular health. Whether these benefits are lasting, however, is less clear.
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Downsides of the Carnivore Diet
Due to its highly restrictive nature and complete elimination of the majority of food groups, there are many downsides to the carnivore diet.
High in Fat, Cholesterol, and Sodium
Given that the carnivore diet consists solely of animal foods, it can be high in saturated fat and cholesterol. Saturated fat may raise your LDL (bad) cholesterol, which may increase your risk of heart disease. However, recent studies have shown that the link between saturated fat intake and heart disease risk may not be as strong as previously believed. Still, consuming high amounts of saturated fat on the carnivore diet may be of concern. No research has analyzed the health effects of eating animal foods exclusively. Therefore, the effects of consuming such high levels of fat and cholesterol are unknown.
Moreover, some processed meats, especially bacon and breakfast meats, also contain high amounts of sodium. Eating a lot of these foods on the carnivore diet can lead to excessive sodium intake, which has been linked to an increased risk of high blood pressure, kidney disease, and other negative health outcomes. Red and processed meat intake has also been linked to higher rates of certain types of cancer, including colon and rectal cancer.
Lack of Certain Micronutrients and Beneficial Plant Compounds
The carnivore diet eliminates highly nutritious foods like fruits, vegetables, legumes, and whole grains, all of which contain beneficial vitamins and minerals. While meat is nutritious and provides many micronutrients, it should not be the only part of your diet. Following a restrictive diet like the carnivore diet may lead to deficiencies in some nutrients and the overconsumption of others. What’s more, diets that are rich in plant-based foods have been associated with a lower risk of certain long-term conditions like heart disease, certain cancers, Alzheimer’s, and type 2 diabetes. This is not only due to the high vitamin, fiber, and mineral contents of plant foods but also their beneficial plant compounds and antioxidants. The carnivore diet does not contain these compounds and has not been associated with any long-term health benefits.
Absence of Fiber
Fiber, a non-digestible carb that promotes gut health and healthy bowel movements, is only found in plant foods. Thus, the carnivore diet contains no fiber, which may lead to constipation as a side effect. Additionally, fiber is incredibly important for the proper balance of bacteria in your gut. In fact, suboptimal gut health can lead to a number of issues and may even be linked to colon cancer. In fact, one review found that a high-protein, low-carb diet may increase your risk for gut inflammation. When your body digests large amounts of protein, it creates potentially harmful byproducts in your gut. These byproducts may have a negative effect on the health of your bowels. Overall, following the carnivore diet may harm your gut health.
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Suitability for Certain Populations
The carnivore diet may be especially problematic for certain populations. For example, those who need to limit their protein intake, including people with chronic kidney disease, should not follow the diet. Also, those who are more sensitive to the cholesterol in foods, or cholesterol hyper-responders, should be cautious about consuming so many high-cholesterol foods. Furthermore, certain populations with special nutrient needs would likely not meet them on the carnivore diet. This includes children and people who are pregnant or lactating. Lastly, those who have anxiety about food or a history of disordered eating should not try this diet.
Sustainability
The carnivore diet is difficult to follow long term and does not offer much variety. The restrictive nature of the carnivore diet can make it hard to follow consistently. Social situations, food variety, and personal preferences may all pose challenges. For many carnivore dieters, maintaining this way of eating over time requires significant planning, preparation, and motivation. In addition, people with certain medical conditions, such as heart disease, diabetes, or high blood pressure, should consult their healthcare provider before starting the carnivore diet, as its low fiber content may not align with their specific health needs.
Adding Vegetables: A Balanced Approach
Once you introduce vegetables, you’re no longer following a carnivore diet, you’re following a more balanced, nutrient-dense eating pattern that includes both animal and plant foods.
Mitigating Risks of Red Meat Consumption
Epidemiological evidence shows that high consumption of red meat increases the risk of developing cancer, while the consumption of fruit and vegetables has been shown to have an opposite, as well as protective, role. A study found that the consumption of approximately 30 g/die of leafy vegetables reduced the risk of mortality by about 22%, and a strong association with mortality was observed in subjects with metabolic dysfunction-associated fatty liver disease (MASLD), although it is a cohort that adheres very closely to the Mediterranean diet, because it consumes little meat.
Several mechanisms may explain the association between MASLD and meat consumption, including hepatic lipid accumulation, hepatic insulin resistance, and oxidative stress. A cross-sectional study, conducted using 2198 subjects, identified a positive relationship between red meat consumption and GGT. GGT, in addition to being a biomarker of fat hepatic accumulation and insulin resistance, may be considered a nonspecific indicator of oxidative stress, leading to the hypothesis of a role of oxidative stress in the development of chronic diseases related to meat consumption.
Addressing Nutrient Deficiencies
Removing vegetables from your diet can significantly reduce nutrient variety, as plant foods, particularly leafy greens, offer various health-promoting bioactive compounds not typically found in animal products. These include polyphenols, flavonoids, and prebiotic fibers that play a role in metabolic function, antioxidant defense, and gut microbiome diversity. Leafy greens also provide key nutrients, including vitamin C, vitamin K, folate, and magnesium, contributing to blood cell integrity, bone health, and cellular function. In their absence, individuals must rely on nutrient-dense animal products such as organ meats and seafood to fill dietary gaps.
Vitamin C deficiency can develop within weeks, leading to fatigue, joint pain, and impaired wound healing. Folate deficiency affects red blood cell production and can cause anemia, characterized by fatigue, weakness, and shortness of breath. The fiber in vegetables promotes healthy digestion, regular bowel movements, and prevents constipation. Vegetable consumption is associated with reduced risk of several types of cancer, particularly colorectal cancer.
A Study on Red Meat and Leafy Vegetables
The American Cancer Society (ACS) and the International Agency for Research on Cancer (IARC) have reported that worldwide, one in five people develop cancer in their lifetime. According to 2023 estimates, the most frequent forms are those of breast, colorectum, bladder, lung, and prostate. Cancer therapy is increasingly complex, with the role of diet, nutrition, and physical activity as adjuvants to therapy, with the goal of improving treatment efficacy and reducing the acute and long-term toxicity of surgery, chemotherapy, and radiation.
The WHO-IARC classified red meat as probably carcinogenic in humans (Group 2A). The World Cancer Research Fund and the American Institute for Cancer Research (WCRF/AICR) recommend a consumption of less than 500 g/week of red meat , because it is positively associated with prostate, pancreatic, and colorectal cancer . Red meat is defined as unprocessed muscle meats, including beef, veal, pork, lamb, mutton, horse, or goat meat . Experimental studies have identified several components of red meat that promote carcinogenesis, many of which are formed during the cooking or the digestion of meat. N-nitrose compounds (NOCs) are formed in the digestive tract, while heterocyclic aromatic as amines (HAAs) are formed in well-done cooked meats and poultry. Polycyclic aromatic hydrocarbons (PAHs) are formed in smoked meats and meats cooked under the flame. All these chemical components may exert a pro-carcinogenic effect because they cause direct DNA damage to the double helix; in fact, during cell division, mutations may occur leading to tumor development.
Despite the evidence, moderate consumption of red meat, as a part of a healthy and balanced diet, does not lead to health problems. In fact, red meat is an important source of protein, because it contains all essential amino acids, and also highly bioavailable iron, zinc, selenium, and B vitamins, especially vitamin B12 . For a balanced diet, the daily consumption of vegetables is also among the 10 recommendations for cancer prevention compiled by the AIRC-WCRF. A diet rich in plant-based foods is associated with a reduction in the risk of developing chronic degenerative diseases including cancers, due to the presence of several nutrients and phytochemicals with protective, anti-inflammatory, and anti-oxidant effects. A recent meta-analysis demonstrated an inverse association between fruit and vegetable intake and the risk of cancer and all-cause mortality. In particular, for total cancer risk, an inverse association was observed with the consumption of green-yellow vegetables and cruciferous vegetables. However, further studies are needed to evaluate the effects of different types of vegetables.
Adherence to a healthy and balanced diet is also one of the main tools for the prevention and management of metabolic dysfunction-associated fatty liver disease (MASLD). MASLD, formerly known as non-alcoholic fatty liver disease (NAFLD), is the leading cause of liver dysfunction in the world today. There is currently no specific treatment for this condition other than lifestyle correction. A recent study showed that a healthy diet, based on the consumption of fruits, vegetables, and nuts, as well as important sources of vitamin A, vitamin C, pyridoxine, and potassium, is inversely associated with the risk of MASLD.
A cohort study aimed to evaluate the protective role of vegetables and their interaction with red meat in preventing cancer mortality in a cohort resident in Southern Italy.
The study involved 1646 subjects derived from a cohort of the Multicenter Italian study on Cholelithiasis (MICOL), approved by the Minister of Health. The MICOL study is a systematic study of a random sample (draw step of 5) from the electoral rolls of Castellana Grotte. The study began in 1985 and continued in 1992, 2005-2006, and 2013-2016. In 2005-2006, using the same sampling scheme, this cohort was supplemented with a random sample of subjects (called “PANEL Study”) aged 30-50 years to compensate for the aging of the cohort.
Red meat consumption (g/die) was categorized based on data from the World Cancer Research Fund International at 50 g/die, and leafy vegetable intake was based on the median values of our distribution (>28.49 g/die vs. ≤28.49 g/die). Mortality rates for malignant cancers were updated on 31 December 2023 and diseases were classified based on ICD-10, considering cancers of the lip, oral cavity, pharynx, skin and soft tissue, digestive system, respiratory system and intrathoracic organs, breast, female and male genital organs, urinary system, lymphatic tissue, and hematopoietic tissue and related tissues, as well as some other tumors.
Lifestyle and anthropometric assessments were performed by a physician during examination at the study center. Smoking status was based on the single question, “Do you smoke?” The level of education was expressed as years of schooling. Body mass index (BMI) was calculated as kg/m2. Blood was collected from all subjects in the morning after an overnight fast. Serum was examined for glucose, as well as lipid profile (total cholesterol, HDL, LDL, triglycerides, and fatty acids). Glucose concentrations were determined using the glucose oxidase method, and lipid concentrations (total cholesterol, HDL, LDL, triglycerides, and fatty acids) were measured using an automated colorimetric method (Sclavus, Siena, Italy) (Hitachi; Boehringer Mannheim, Mannheim, Germany). An automated system measured total bilirubin, GOT, GGT, and SGPT, in accordance with standard laboratory procedures (UniCel Integrated Workstations DxC 660i, Beckman Coulter, Fullerton, CA, USA). The serum was separated into aliquots. One aliquot was immediately stored at −80 °C. The second aliquot was used to test biomarkers through standard laboratory techniques in our laboratory. Diet and eating habits were investigated by administering a previously validated food frequency questionnaire, administered during the visit. The questionnaire is organized into 11 sections representing food macro areas: grains, meat, fish, milk and dairy products, vegetables, legumes, fruits, various foods, water and alcoholic beverages, olive oil and other edible fats, coffee/sugar, and salt. Subsequently, each food (86 foods in total) was converted to mean daily intake in grams, as previously carried out for other studies.
Males were more prevalent among subjects who ate >50 g/die red meat (76.83% vs. 51.41%, p < 0.001) and those in this category were younger (61.84 ± 8.88 vs. 66.06 ± 9.43 years, p < 0.0001), showing statistically significant differences. Smokers showed the same trend as major red meat consumers (22.39% vs. 13.02%, p < 0.001), again showing statistically significant differences. Systolic pressure was lower in the second group (136.30 ± 95.37 vs. 139.12 ± 82.62, p < 0.0001) and hypertension was lower in subjects who ate less red meat (39.15% vs. 51.16%, p < 0.001). Lower levels of blood parameters were observed in the first group, for HDL (87.71 ± 618.38 vs. 58.60 ± 267.44, p = 0.01), triglycerides (200.22 ± 627.46 vs. 142.39 ± 279.00, p = 0.002), and GGT (174.75 ± 1233.01 vs. 82.94 ± 801.90, p = 0.0002), all of which were significantly different. Vice versa, lower levels of SGPT were observed in the second group (18.83 ± 14.17 vs. 25.12 ± 268.64, p = 0.0002). Leafy vegetable intake was associated with red meat intake, with a higher intake in subjects consuming > 50 g/die (56.76% vs. 48.09%, p = 0.01). Higher grams of consumption of red meat show a positive association with the highest risk of mortality (HR = 2.02, p = 0.001, 1.36 to 3.01 95% C.I.), but a statistically significant trend is observed for the interaction between red meat and leafy vegetables. In the category with a higher red meat consumption combined with a lower or high leafy vegetable intake, a reduction of risk was observed, which was statistically significant (HR = 2.36, p = 0.002, 1.38 to 4.01 95% C.I.; HR = 1.85, p = 0.03, 1.06 to 3.22 95% C.I).
Epidemiological evidence shows that high consumption of red meat increases the risk of developing cancer, while the consumption of fruit and vegetables has been shown to have an opposite, as well as protective, role. In this study, the consumption of approximately 30 g/die of leafy vegetables reduced the risk of mortality by about 22%, and a strong association with mortality was observed in subjects with MASLD, although it is a cohort that adheres very closely to the Mediterranean diet, because it consumes little meat.
Addressing Gut Health
Gut microbiome disruption occurs when beneficial bacteria lack their primary food source. Beneficial gut bacteria rely on fiber to produce short-chain fatty acids, which help regulate immune function . The fiber in vegetables promotes healthy digestion, regular bowel movements, and prevents constipation.
Potential Modifications
Many individuals modify the strict carnivore approach into a more practical version that prioritizes animal-based nutrition. For example, some incorporate low-irritant plant foods, such as herbs, olives, or fermented vegetables. This allows for added flavor, micronutrient variety, and better digestion for individuals who may not tolerate fiber-heavy plants. Others follow a minimalist version like the “lion diet,” which consists solely of ruminant meat, animal fat, salt, and water. This ultra-simple approach appeals to those who want to eliminate all dietary variables and observe how their body responds. Additionally, dairy-based variations include full-fat cheeses, butter, and yogurt, which contribute to calcium intake and can assist in satiety and gut comfort if well-tolerated.