I read an article in Vegetarian Times (March 2009 issue) that Kale and Adzuki beans are in the top 10 Super food list (# 6 & 7 respectively). Cooking kale increases its antioxidant level, but over-doing has the reverse effect. So this curry is super healthy and tastes pretty good too.
Kale is a sturdier green compared to spinach and does not cook down to a mush and as mentioned before overcooking makes it not so healthy also. This is a dry curry that goes well with rotis or rice and pappu (dal).