From your 'My Hub' page (please see below)
On the left hand side of your account, you will see the side menu in which you can select 'Groups'.
This will show any groups you have created
Click the 'Nutrition' tab from the 5 options at the top of your page.
And by clicking 'Create Nutrition Group' at the bottom of your screen
You will then be able to create a nutrition group
And once created you can simply select the group to add any nutrition plans.