GET IN THE KETO ZONE The Keto Zone® is the point at which your body switches from burning carbs as fuel to burning fats as fuel. This transition is referred to as the Keto Zone®. When you follow Dr. Colbert’s Keto Zone® Diet you will burn fat, optimize cognition and improve energy levels. When diet isn’t enough, look to Dr. Colbert’s science based Keto Zone® Nutritional System. The Keto Zone® Nutritional System was developed to limit the time it takes your body to enter the Keto Zone®, while also supplying your body with essential fats, protein and enzymes.