The ill feeling that may occur in the first few days after initiating a ketogenic diet is commonly referred to as the keto flu. Fortunately, this feeling is temporary and can be completely or partially alleviated by following a few precautionary measures. First, consider your electrolytes. A deficiency in sodium, potassium, or calcium could make you feel sick. Second, consider your hydration level. It’s easy to get dehydrated at the beginning of the ketogenic diet. Third, consider your fiber intake. If you’re not getting enough fiber, you could become constipated. The takeaway: replenish your electrolytes, drink a lot of water, and make sure you’re getting enough fiber.