Diets low in carbohydrates and high in animal fat—such as Keto and Paleo—can shorten an individual’s lifespan by up to four years, according to a new study published by The Lancet Public Health. Scientists gathered self-reported data from 15,400 individuals in the United States over the course of 25 years and found that participants that avoided carbohydrate consumption and replaced caloric intake with beef, lamb, pork, chicken and cheese had an increased risk of early death. “Low-carb diets that replace carbohydrates with protein or fat are gaining widespread popularity as a health and weight-loss strategy. However, our data suggests that animal-based low carbohydrate diets, which are prevalent in North America and Europe, might be associated with shorter overall life span and should be discouraged,” study researcher Sara Seidelmann said. “Instead, if one chooses to follow a low carbohydrate diet, then exchanging carbohydrates for more plant-based fats and proteins might actually promote healthy aging in the long term.” Similarly, a recent study published by the American Heart Association found that individuals that consume a diet high in animal-based protein increase their risk of heart failure by 43 percent, which increases to 49 percent when the protein is derived from dairy products.