The carnivore diet is a fad diet that involves consuming only animal products such as meat, eggs, and dairy. It is also known as a zero-carb diet because it excludes all produce, as well as grains, legumes, nuts, and seeds. The carnivore diet is associated with pseudoscientific health claims and can lead to deficiencies of vitamins and dietary fiber, and increase the risk of chronic diseases. The lion diet is a highly restrictive form of the carnivore diet where only beef is eaten. The idea of an exclusive meat diet can be traced back to the 19th century, and it has been advocated by various individuals over the years. Unlike other similar diets, there is no one unifying source material or set of “laws” for the carnivore diet, and rules are usually set by the practitioner based on their goals and preferences. The carnivore diet is a type of Primal and ancestral diet, but those diet types allow for more produce. While some people use the carnivore diet as a “reset” or temporary elimination diet to address certain health issues, no controlled studies support claims that the carnivore diet can help eliminate health issues. It lacks beneficial nutrients, including fiber and plant compounds like antioxidants, and may be unsafe for some people.