Hey! The Ketone Strips are strips that you can buy in the diabetic section of any store, and they measure what state of ketosis that your body is in. When you stop eating carbs, well alot of them, after 48 hours your body goes into ketosis which means it is using the fat in your body for fuel, and when its done, your body lets off ketones. The strips you dip in your urine, and they will turn from pink to purple, depending on how many ketones are in your body. I honestly don't like them because some people NEVER go into ketosis on Atkins and lose 50+ pounds, then some people do and they work for them. Hope that helped!