I've been testing FastBot in the beta. I would say, it is one the simplest and useful fasting apps out there. I like the native design as well. I like how the app shows what happens when you choose different fast durations (goals). I would like to see the app become even more powerful.

Diet-Free Weight Loss Fasting was found to be more effective than calorie restriction at increasing fat loss while simultaneously preserving muscle tissue. Reduce Insulin Resistance Several studies have found that fasting may improve blood sugar control, which could be especially useful for those at risk of diabetes. Increases Growth Hormone Human growth hormone (HGH) is a type of protein hormone that is central to many aspects of your health like Metabolism, Weight Loss, and Muscle Strength. Friends Invite your friends and share fasting data to motivate each other. A powerful insight analyzer allows you to understand how different fasting stages improve your health and reduce body fat. Blood sugar analysis helps you understand how your insulin sensitivity changes during fasting intervals. FastBot provides an intelligent recommendations system that gives you hints on reducing weight and body fat.