While a person may be able to consume some form of the carnivore diet in the short run without many ill effects, it’s clear that the diet comes with significant restrictions that can eventually prove detrimental to human health. Nutritional deficiencies, like a lack of vitamin C, can soon lead to illness, like scurvy. And in the long run, excessive consumption of red meat, which is rich in protein and fat, but deficient in carbohydrates and dietary fiber, increases the risk of heart disease and certain cancers.