If we would eat only crops we grow we could free up massive amounts of land and stop the soil erosion. The animal industry emits more green house gases then all vehicles on earth, it is the worst possible solution which also speeds up the climate issue, droughts etc . We could save large amounts of water as well and by doing this we will create a sustainable food source capable of producing food for 8 Bil.
The problem you describe is very real but humans have evolved to eat meat and eating only crops should not be enforced on the population, luckily a solution already exists and only depends upon consumer adoption when it becomes economically viable to mass produce. I'm sure from your name "the biochemist" you have probably already heard of lab grown meat
https://en.wikipedia.org/wiki/Cultured_meat. If it compares to real meat I would happily make the switch.
We did not evolve to eat meat, we are not carnivores, coulden´t be more wrong. We have been feeding on vegetables or rather nuts fruits and roots ect for millions of years as apes, meat is new on the menu and NO evolution has taken place since then. It is time to stop denying that meat is the worst option and brings only diseases not good health! I am a professional biochemist and this is just plain facts get it right!
So... according to TheBioChemist (his very screen name inspires confidence in me that what he's saying HAS to be true), "we" have been vegetarians for millions of years as apes, and NO evolution has taken place since then. So I guess the plain facts is that behind TheBioChemist's computer screen is an ape busy typing all this crap in.