The info on genes and needing meat to feel healthy for people with certain genes is new for me.Very interesting. I don't think I have these genes. I only eat meat about twice per week but the times in my life I tried to cut it out completely I would just be exhausted and in a brain fog al the time. I have a low red blood cell count (normal, but on the very low end of normal) so when I do eat meat, I go for the higher iron meats. Eggs and sardines are also helpful to keeping my energy level steady.
I learned that if you want to eat vegetarian, you can’t just take out the meat of your diet without replacing it with some kind of ‘substitute’ like beans, seeds or nuts. And to keep your level of iron up by eating green veggies and other food high in iron.
Long time ago I was on a trip in Greece for 6 weeks and ate vegetarian, but the food in restaurants was very simple in those days. Green spinach like veggies were not available. After 5 weeks I started to feel dizzy and for me it was obvious I had eaten not enough food with iron in it.
I recognised it from when I was a teenager. After a two meals with liver and red meat I felt okay again.
To people who want to eat vegan, they recommend to take special vitamin/essentials tablets with B vitamins that are very rare in a vegan diet.
The article isn’t very specific. But I can imagine that there are differences in our genes that contribute is specific needs to a certain extend.