Also, Catholics have eaten all sorts of foods provided by God for ages (including the Jєωs before their Covenant was ended in 33 AD) -- meat, grains, vegatables, and milk products.
As I see it, those are the things God intended for us to eat.
Now all these things are good, but it is wholesome for the soul to give up that which is lawful (e.g., meat) for a higher purpose from time to time -- for example on Fridays, ember days, vigils, etc. For that matter, food is a good thing but it is good to deny oneself frequently by fasting.
Until the modern age of grain-fed cows, industrially produced chickens, antibiotics, etc. meat was much more expensive, so people didn't eat it at every meal. I'm sure that's thrown off the balance God intended, which is why so many people have poor health today.