Everyone has to figure out and decide what works best for them.
I was mostly vegetarian for a number of years, and then went
through a period where I ate alot of meat. I gained quite a bit of weight,
and was generally unhealthy.
Then I had an experience where I woke up from sound sleep with the word "UREA" very loud in my head. A blood test confirmed that my blood type does best with a vegetarian diet. At the beginning of the year, I went back
to a mostly vegetarian diet and lost all of the weight and more.
However, I must also attribute that success to cutting down or eliminating caffeine, dairy, processed food, alcohol, prescription meds and a number of other unhealthy items. I pretty much each plant based foods, including beans, rice, vegetables, fruit, nuts, seeds. I still eat small amounts of meat and animal protein including chicken, fish, eggs, and cheese made from goat's milk.
I also take a supplement called IntraMax, which has over 400 organically-sourced nutrients, including a hefty dose of B12. It ain't cheap, but I learned the hard way that you pay the price for things one way or the other-your health or your wallet.
I consider my health to be a pretty important asset.