Collegeguy, considering you can make a lot of tasty food off beans, use soy in very creative ways, or just make eggs daily for breakfast.
Not that hard to do tbh.
No nutritunal supliments needed. Maybe children below age 3 since they need some other amino acids and I don't know exactly what contains them.
In the end you'd have to change "meat" into "beans/soy". Not that big a change. Would be forced to learn new recepies.
-Note, not vegetarian since meat is fucking tasty. I am thinking about dropping to a diet of meat twice a week as an aside (mostly to make my geologica footprint smaller).
Edit:
You actually already do live your life by a dedicated shopinglist.
"Meat or I die", I'm just trying to point out it's not true.