Man seeks to change the foods available in nature to suit his tastes, thereby putting an end to the very essence of life contained in them.
I switch back and forth between baby kale and baby spinach. I little trick that works well for me is to buy in bulk from Costco and store in the freezer for better storage. I make kefir from coconut milk and the sourness really offsets the bitterness of greens. I have a Vitamix and really pulverize the greens before adding other ingredients like a banana and berries. The other thing I add from time to time is chia seeds.
I'm also told Mung Bean starch is easily available and just as good, or better than potato starch.
If you are interested in gut health Dr.BG has a good series on the care and feeding of gut flora. Resistant Starch is a great food-source for gut microbes, hence the potato starch.