MyFitnessPal is one of the more popular diet tracking applications. There are paid plans that allow you to focus on a low carb diet, but we can still track a keto diet with some modifications to the default settings.
First, make sure you have a MyFitnessPal account and have downloaded the app to your smart phone. For this tutorial we're going to need to make changes on the MyFitnessPal website.
Once you log in click on the Goals link in the top menu:
Next click the edit button next to "daily nutrition goals":
Next set your carbohydrates to 5%, Fat to 65%, and Protein to 30%
Save your change and you are now ready to start tracking your keto diet.