You are able to remove specific information from your account. In order to do so, you will need to open the app > tap Trends > tap Historical Records > select the date you would like to delete data for > slide left on the data you would like to delete to reveal the red delete button > tap the red delete button.
To delete a user account: go to my account > put your finger on the user you want to delete and swipe to the left. > click delete. Please be aware, you cannot delete the primary user.