Wait, what’s this about raw spinach?
As with all diet data though, YMMV. Some people eat loads of yaw spinach and never develop kidney stones.
Certainly if you have a familiar history of them, you should avoid raw spinach. Cooking it reduces the oxalates.
Through it all, it seems a general rule of thumb is:
Eat whole foods. If it requires processing in a factory, avoid it. This includes many things that you might not intuitively think of. Vegetable oils, for example are a highly processed food.
Aside from avoiding processed foods, and eating whole ingredients... Yes, eat a variety of different foods. Eat vegetables, eat carbohydrates, eat meat. Just don't eat too much of any one thing, and if you can identify something that doesn't sit well with you, avoid it!
Me, I don't eat spinach anymore. Never liked it to begin with. I have eaten enough of it already to last me to the end.
Nothing indicates that the decimal point error ever was made, but the account about it will most likely live a long and colorful life, just like its parent myth
But seriously, you described three layers of misconceptions in this comment thread, how is anyone supposed to know "the real truth" about anything food related, if spinach alone is such a hard subject?
Actually true for most vegetables we eat, they're all the same plant (Brassica oleracea).
Apparently there is no documentary evidence why an 1870 measure of spinach's iron content was exaggerated. The paper cited does not explore whether it ever was exaggerated, or what its actual iron content then or now might be.
I read various reports indicating that modern vegetables have much less of various nutrients than older, slower-growing or smaller-yielding varieties, and have no idea how I might evaluate such claims. Maybe spinach harvested in 1870 had more iron than highly-fertilized 1930 varieties, never mind 2021 varieties no one, to my knowledge, has bothered to measure. Or maybe not.