On keto, fat becomes your main fuel—but quality matters. Traditional fats like butter, tallow, lard, bacon grease, olive oil, and cream support stable energy and satiety. Functional fats like coconut oil can enhance ketone production. In contrast, industrial seed oils and highly processed fats may disrupt metabolism. The key is not just eating more fat, but choosing real, minimally processed fats that the body recognizes and uses efficiently.