How do I tell what % of the total calories that are listed on a food label come from fat, protein or carbs. I am trying to write myself a new diet and I am going to base it on a 50/20/30 ratio (pro/carbs/fat). Its kinda hard to do when I can't figure out the percentages from just looking at food labels. Can somebody point me in the right direction? Or am I going about it all wrong.