“As a dietician, I’m a big proponent of whole foods, so if someone can sit down and have a steak, I think that’s better post-workout,” says R.D. and trainer Albert Matheny, co-owner of Soho Strength Lab. “But if you’re busy and running around and need some protein, you can throw this in some water and go.” The real trouble is in choosing which to throw in the blender. Whey? Casein? Soy? A vegan blend of pea, hemp, and brown rice? And which brand? We tapped the expertise of Matheny, who’s also the founder of Source Organic Whey, and Jenna Bell, R.D., Ph.D., a two-time Ironman finisher and the co-author of Energy to Burn, to bring you this guide to protein powders. Here are five easy steps to choosing the healthiest smoothie-booster to meet your post-workout or everyday nutritional needs…Find out with Well+GoodNYC’s The Protein Powder Primer.