A new study was published in the news citing evidence that Homo Erectus may have been using fire and cooking food as early as 1 million years ago.
That would mean people were eating cooked meals before people were people ( Homo Sapiens ).
Outside of scientific circles this may only be significant to raw foodists, many of whom justify eating only raw foods on the belief that it is the diet human beings evolved on and what we are adapted to.
It is amazing how crazy people are over kale. Yet, there is a very tasty, friendly and available vegetable that has over 3 times the usable calcium of kale and over twice the usable calcium of a cup of cow’s milk. It is called
It cooks as quickly as spinach. It can be found in any Asian market. Googling on “choy sum seeds” quickly reveals a variety of sources for growing your own. Searching youtube on “choy sum” will find you a list of videos demonstrating how to cook it.
I think that with all of the interest I read about kale, eating it, making recipes for it, even growing it in pots for apartment dwellers — that it is PAST the time that choy sum becomes the next “crossover hit” to make it into mainstream American markets.
There are a number of vegetables that are now in mainstream supermarkets that were not there when I was a kid. Most are not as deserving as choy sum, IMO. It is a nutritional powerhouse. Starting asking for it at your local farmer’s market, mainstream supermarkets, co-ops, Whole Foods, TJ’s, etc.
Remember, you read about it here first! 
In this video Dr. Michael Greger M.D., the director of Public Health and Animal Agriculture at the Humane Society of the United States explains that eating kale may give a boost to human immune systems, but that cooked kale will help the human immune system much more than raw kale.. You can go to the original link at nutritionfacts.org for sources cited and more information about this video.