It depends on the type of peanut butter you consume. Some peanut butter brands contain added sugars and other carbohydrates that may increase your blood sugar levels and kick you out of ketosis. It is crucial to read the nutrition label and ingredients list before purchasing peanut butter. Look for peanut butter that is all-natural, sugar-free, and has no added oils. The most keto-friendly option is unsweetened peanut butter that has been made with just peanuts and salt.