We Asked Dietitians About the Potential Health Risks of an Animal-Based Diet

Animal-based diets are similar to the more commonly known carnivore diet. It focuses on consuming mainly animal products, including grass-fed red meat, organ meat like liver, eggs, and dairy. Other foods, like fruits and vegetables, are included more sparingly.

Social media users claim that eating large amounts of protein and fat—while limiting carb intake—helps with weight loss and overall health. Dietitians say this approach is often challenging to maintain and can put people at risk for other health issues.

Health Risks of an Animal-Based Diet

Animal-based diets are linked to various bad health outcomes, including increased risk of cancer, vitamin deficiency, heart disease, and obesity, according to Beth Czerwony, MS, RD, LD, a registered dietitian with the Cleveland Clinic Center for Human Nutrition.

“There are more cons than pros when looking at any exclusive food group diet,” Czerwony told Verywell.

A 2023 analysis suggested that low-carb, high-animal-protein diets were linked to an increased risk of heart disease. People on those restrictive diets were more likely to have higher LDL “bad” cholesterol, impaired vascular function, and inflammation than people eating a diet richer in unprocessed carbohydrates, such as beans and legumes.

Major health groups, including the American Heart Association, also advise against these restrictive animal-based diets, said the study author Rami Salim Najjar, PhD, a postdoctoral fellow at the Institute for Biomedical Sciences at Georgia State University. 

“The main problem with them is that they contain lots of saturated fat, and saturated fat is directly linked to heart disease, not just because it raises cholesterol, but because it also increases the inflammatory response in the body,” Najjar said.

Other Health Risks to Know About

A restrictive diet also puts you at risk of issues such as scurvy, constipation, and essential fatty acid deficiency, according to James Daniel John, MS, RD, a clinical dietitian at Loyola Medicine.

“Some of the commercially branded animal-based diets I’ve looked at demonstrate a worrying disregard for meeting basic nutritional needs and would be fairly compared to snake oil,” John said.

Can an Animal-Based Diet Help You Lose Weight?

While an animal-based diet might help you lose weight, that loss may not come from body fat, said Najjar.

A 2015 study comparing high-fat, low-carb diets with higher-carb, low-fat diets found that people in the high-fat group lost less body fat than those in the low-fat group, even though they lost more weight overall. 

Much of the weight loss in the high-fat, low-carb group came from lean mass rather than fat.

“It’s not necessarily muscle. It could be water as well. But the people on the low-fat diet lost more body fat,” Najjar said.

A Less Restrictive Approach to Eating

Because animal-based diets are so restrictive, Czerwony advises going “back to basics” to improve your health. This includes:

• Increasing vegetable and fruit intake to 5 servings per day
• Eating lean proteins like fish and chicken
• Sticking to unsaturated fats
• Eating more whole grains, beans, and other plant-based proteins 

“Animal-based diets have been shown to increase health-related diseases, whereas including a variety of foods from all food groups has been shown to decrease weight, heart disease, and improve gut health and blood sugar control,” Czerwony said.

And don’t discount the benefits of getting more fiber in your food, said Najjar. Fiber is found in whole, unrefined plant foods like sweet potatoes, beans, and brown rice. 

“The more fiber you eat, the lower your risk of dying, essentially, from any chronic disease,” Najjar added. “And fiber is the thing that 97% of the country is low in.”