Whey and casein are two common protein supplements on the market. Old school practices would have you believe that you MUST drink a whey isolate shake immediately after your workout, and you MUST drink a casein shake before bed or you will lose all your gains. Is there any truth to this claim?
These two proteins actually have more similarities than differences. Whey and casein are both complete proteins from milk with similar amino acid profiles, and both have good bioavailability. Both should be suitable for individuals with lactose intolerance, as lactose is a milk sugar, and whey and casein are milk proteins (although some individuals may still have a sensitivity to these supplements). This is not the case with anaphylactic allergies to dairy, where milk proteins, usually casein, are the culprit of reactions.
Whey empties from the stomach rather quickly, and amino acid levels in the bloodstream peak in less than an hour. Note that when it comes to whey supplements, whey isolate means that the product only contains whey protein while whey concentrate indicates a protein blend that contains mostly whey.
Casein is considered a slower-digesting protein. It coagulates once it reaches the stomach causing it to empty more slowly. When you consume casein, amino acid levels in the bloodstream take a few hours to reach their peak.
If you use protein powders for macro-friendly desserts, the type you use can make a huge difference as @rebekahclementson can attest to! Casein tends to impart a creamier, thicker texture in shakes and protein ice creams and is less likely to result in dry baked goods. Whey can be used for baking as well, but it lends itself to dryness and generally requires a moisturizing ingredient to prevent this, such as banana, egg, yogurt, cottage cheese, pumpkin etc. Per Rebekah, casein or protein blends are generally best for baking and for protein ice cream. Thanks for sharing your expertise!
Both proteins result in net protein synthesis after resistance training. Daily protein requirements vary person to person, but generally you should aim to consume 20-30g within a couple of hours before exercise or shortly after. Both whey and casein are great supplements, but neither is necessary. And you can drink your protein shake, whatever the type, after your workout, before bed, or really whenever you feel like it.
-Katy Hair, RD, LDN, CPT