Keto is a low-carb, high-fat diet with moderate-protein.  

This type of eating pattern involves decreasing carbohydrate consumption while simultaneously increasing fat intake with a moderate amount of protein. The goal of keto is to help the body achieve ketosis, which is a metabolic state where your body “burns fat for fuel” instead of using carbs. This usually takes 4 days to achieve if you eat 1-2 oz of carbs per day. It may take longer depending on certain factors such as age, activity level, and metabolism. Having a cheat day can take you out of ketosis and it may take a week to get back into that metabolic state. Doing cycles of keto is not unheard of and consists of doing 5-6 days of standard keto percentages followed by 1–2 days of higher carb consumption, which is meant to replenish your body's depleted glucose reserve.

The percentages for keto are very different than any other plan. A more relaxed approach to keto dieting is 10% of carbs a day from daily caloric intake while not tracking fat or protein intake.