Tesla and Mahatma Gandhi were vegetarian, just like 500 million people in India today and Albert Einstein, Leonardo DaVinci, Isaac Newton, Pythagoras. Did you know India is the most vegetarian country in the world? :)
We will live on energy as Nikola Tesla predicted, without eating. From nitrogen in air and/or dust and/or water we will make all food we need to build material body and live without eating eventually. Food or water, food or dust, food or air are the same quarks rearranged, same protons, neutrons rearranged. We'll eventually get nutrients provided directly to cells, and waste chemicals recycled by nanobots so we don't eat.
For the transition period, we can add some coherent biophotons and other things that keep us young and we mimic natural fruits and veggies totally. In due time we will understand more about foods and what they have that keep us young. A cell is like a small chemical factory with 100,000 chemical reactions each second. We will discover how trillions of cells work together and what biophotons, etc in foods facilitate that communication :)
With the chemistry advances, it will be possible to get chemical nutrition in a simple shake that has all things you need, just drink it 2-4 times a day. We won't grow plants for food eventually, but make all individual compounds we need, essential nutrients, mix them and create flavored mixes, drinks, cakes, etc that are the "food".
We will make individual compound synthesis so cheap for aminoacids, etc that it will be easier to eat aminoacids only no proteins anymore. That way, we spend less energy breaking proteins into aminoacids in our digestive system.
It is really wasteful to spend hours a day shopping, cooking, thinking about food when you can just order a powder thrice a year and mix it with water and drink it. Agriculture will become obsolete.