Understanding the 21 Day Fix Containers 04/03/2017 Congrats! If you're here you have likely already decided that the Portion Fix system is just what you need to get your nutrition on track. I'm here to help you navigate it :) The 21 Day Fix is meant to keep eating simple and to help retrain your brain for healthy eating as a habit! Here's how you can use the containers properly so you can meal plan with ease and also see better results! First, let’s talk about each container… There are 6 colors corresponding to 6 different types of foods.