Pretty much impossible for me. I live in a very cold and harsh climate, proteins and fats from meat supply the fuel to keep you going when the mercury drops below -40.
We have short growing seasons here, vegetables have to be started in greenhouses or in the house and cold tunnels help to lengthen the season long enough to harvest stuff that takes more than 90 days to mature. Although we can raise pretty good potato's.
We have to irrigate as it is a dry country as well. So for folks in my area to go meatless, just about everything would have to be imported from somewhere else.
This being said, it is great grazing country for cattle, sheep and goats, and abundant wildlife. That makes high quality meat available to everyone.
As it is a high energy food, you don't need to eat as much to keep functioning.
We can raise grains like Wheat, oats and Barley dry land, but corn and legumes must be on irrigated soil.
Fruits can be hard to raise here, but apples, wild berries, rhubarb all do well here and can provide the necessary vitamin c.
Because of the long winters where fresh produce isn't available from local sources, you have to can, freeze or dehydrate to have vegetables through the winter, or have a good cellar for root vegetables.
Meat can be obtained fresh year round, both domestic and wild, so it is the truly viable resource in my country.
I think this way because I produce much of what my family and I eat. If I was just resigned to buying that plastic tasting stuff from wally world, it wouldn't make any difference if I was only grazing or eating meat mixed into a balanced diet, but when you collect wild edibles, raise your garden and livestock including chickens, turkeys and rabbits, hunt and fish, the processed stuff doesn't have any life in it anymore for you.
You can get fat on it, but performing labor intensive work, you fall short. Home grown/produced means you have to eat a lot less to get the energy, without any additives.
You can hardly compare the products.
Has nothing to do with being a vegetarian or the philosophy behind it, just the way it has always been here. Even the local Indians had to live primarily on meat to survive in this climate.
In my case, why mess with what works?