I'm really getting into kefir these days. In case you don't know, kefir is a smoothie-like (but thinner) drink of fermented milk; it's like liquid yogurt. Kefir comes packaged in bottles; the plain flavor is great but pretty tart, so you can also buy versions that are flavored with fruit, and with additional probiotics added for digestive health. Not heavy but very satiating, just a cup of kefir never fails to give me an energy boost; it makes an excellent snack for home or work. Try this kind from Evolve; I got a sample of the Pomegranate flavor and loved it.