You had diabetes because you were likely obese and inactive. Not because you were eating bread, FFS.
I don't understand why it is so hard for people to understand the concept is literally just "calories in minus calories used / out = weight gain or loss." It is simple thermodynamics.
Keto/Paleo diets are among the least nutritious and most difficult to adhere to (most people who claim to follow keto/paleo don't, because it's extremely restrictive), consistently ranking among the worst diets health-wise by nutritional scientists. One of the best is the Mediterranean diet, one which involves no red meat.
> As for all the other stuff, all farming has environmental impact. You can argue degrees of impact,
That's literally what we're saying, and there's plenty of proof.
Beef uses ten times more resources than chicken: https://www.smithsonianmag.com/science-nature/beef-uses-ten-...
You want to help the environment? Minimize your red meat consumption. That alone makes a huge difference. The second biggest difference you can make is minimizing energy use for personal transportation, and the third biggest difference is reducing energy consumption in your home (mostly heating/cooling.)