Ketosis is a metabolic state that occurs when your body doesn’t have enough carbohydrates to burn for energy. Instead, it burns fat and makes substances called ketones, which it can use for fuel. Ketosis has gained a lot of recognition over the years. Several recent studies have shown that when you reach a state of ketosis, your body becomes incredibly efficient at burning fat for energy. It also turns fat into ketones in the liver, which can supply energy for both your body and brain.