Kefir is actually made using kefir grains ... thinner consistency than some of the other varieties out there. Greek yogurt, ...

Few foods are as healthy and versatile as yogurt. But what’s better? Greek yogurt or Icelandic? Dairy or oat or almond? Nonfat, low-fat or whole-milk?

Yogurt and kefir come in dairy and non-dairy as well as plain and flavored options. There is also Greek yogurt—yogurt that's been strained to make a thicker, creamier, and higher-protein yogurt.