calculate your need for protein fat and carbohydrates.
this calculator based on research on multiple users with apple watches, this is the most accurate I can get calories your body burn per day and gives calories and macros you have to eat lose weight in right way.
my formula base on the following website:
http://www.acaloriecounter.com/diet/how-many-calories-should-i-eat-per-day-to-lose-weight/