What are the effects of a carnivore diet?

From the Guidelines

I strongly advise against following a carnivore diet due to its potential to increase morbidity, mortality, and negatively impact quality of life. The carnivore diet, which consists exclusively of animal products and excludes all plant foods, poses significant health concerns. While some proponents claim benefits like weight loss, reduced inflammation, and improved mental clarity, these claims lack substantial scientific evidence 1.

The diet's high saturated fat intake may increase the risk of heart disease, and the lack of plant-based foods may lead to vitamin and mineral deficiencies, particularly vitamin C, fiber, and plant antioxidants 1. Additionally, the high protein content may stress kidneys in susceptible individuals, and the elimination of plant foods may have negative effects on gut health due to the lack of fiber.

A diet rich in animal protein, saturated fat, and cholesterol raises low-density lipoprotein (LDL) cholesterol levels, which can be detrimental to cardiovascular health 1. Furthermore, the restriction of fruit, vegetables, beans, and whole grains from the diet may increase cancer risk, and a very-high-protein diet is especially risky for patients with diabetes, as it can speed the progression of diabetic renal disease 1.

In contrast, a diet based on vegetables, fruits, and whole grains, and low in saturated fat, red meat, and alcohol is recommended for maintaining a healthy weight and lifestyle, particularly for cancer survivors 1. If you're interested in a lower-carb approach, consider less restrictive options like Mediterranean or paleo diets that include plant foods. Anyone considering the carnivore diet should consult with a healthcare provider first, especially those with existing health conditions like heart disease, kidney problems, or diabetes.

Some may argue that the current epidemiological and mechanistic data have not been able to demonstrate a consistent causal link between red meat intake and chronic diseases, such as colorectal cancer 1. However, the available evidence generally suggests that interventions with red meat do not lead to an elevation of in vivo oxidative stress and inflammation, which are usually cited as being part of the underlying mechanisms triggering chronic diseases 1. Nevertheless, the potential risks associated with the carnivore diet outweigh any potential benefits, and a more balanced diet that includes plant foods is recommended to minimize morbidity, mortality, and improve quality of life.

From the Research

Carnivore Diet Overview

• The carnivore diet consists exclusively of animal products and has gained attention for its potential benefits in managing inflammatory conditions and chronic metabolic diseases 2.
• A case study model assessed the micronutrient adequacy of four versions of the carnivore diet against national nutrient reference values (NRVs) and found that it met several NRV thresholds for nutrients such as riboflavin, niacin, and zinc, but fell short in thiamin, magnesium, and calcium 2.

Health Effects and Nutrient Intake

• A survey of 2029 adults consuming a carnivore diet found that participants reported high levels of satisfaction and improvements in overall health, well-being, and various medical conditions, with few adverse effects 3.
• The carnivore diet may offer benefits for managing certain chronic conditions, but its long-term effects and potential risks of micronutrient inadequacies remain to be determined 2, 3.
• A systematic review of observational and intervention studies found that plant-based diets were associated with lower intake of certain nutrients, such as vitamin B12, vitamin D, and iron, compared to meat-eaters 4.

Omega-3 Fatty Acids and Cardiovascular Health

• Omega-3 polyunsaturated fatty acids from oily fish and plants may benefit cardiovascular health, but recent trials have not confirmed this 5, 6.
• A systematic review of 79 RCTs found that increasing LCn3 intake had little or no effect on all-cause mortality, cardiovascular mortality, or cardiovascular events, but may slightly reduce coronary heart disease mortality and events 5.
• Another systematic review of 86 RCTs found that increasing LCn3 intake had little or no effect on all-cause mortality, cardiovascular mortality, or cardiovascular events, but may slightly reduce coronary heart disease mortality and events, and reduce serum triglycerides 6.

Key Nutrients and Potential Deficiencies

• The carnivore diet may be low in certain nutrients, such as thiamin, magnesium, and calcium, and high in others, such as sodium and cholesterol 2.
• Plant-based diets may be low in certain nutrients, such as vitamin B12, vitamin D, and iron, and high in others, such as fiber and polyunsaturated fatty acids 4.
• Omega-3 fatty acids, particularly EPA and DHA, are important for cardiovascular health, but the evidence for their benefits is mixed 5, 6.