Whey Protein vs. Casein Protein

Two forms of popular protein powders are whey protein and casein protein. Whey protein is considered a fast release protein because it's water soluble and easily digested, while casein protein is considered a slow release protein because it's digested slower due to it reacting with stomach acids and curdling. When consumed in appropriate amounts, both sources of protein powder will result in muscle growth. But when should you drink whey protein and when should you drink casein protein? Does it even matter?

A study performed by Willborn et al. tested the 1-RM, muscular endurance, vertical jump, pro-agility and broad jump of 16 collegiate basketball women at the beginning and end of 8 weeks. The women were evenly divided into either a whey protein group or a casein protein group. Both groups consumed 24 g of protein, 4 g of carbohydrates and 1 gram of fat 30 minutes before and immediately after each training session. They found that each group showed significant improvements in body composition, strength and anaerobic performance. When comparing the improvements of the whey protein group to the casein protein group, they didn't see significant differences (1).

However, another study performed by Devries and Phillips disagrees. They found that drinking whey protein stimulates muscle protein synthesis (MPS) more than casein protein after a workout and at rest (2). What is MPS? To put it simply, it's the usage of protein to build muscle. Devries and Phillips's results indicated that whey protein is more effective for muscle growth than casein protein.

The research contradicts itself, but some protein is better than no protein. As long as you consume protein <1 hour before or after training and are eating enough protein throughout the day, you should see an increase in muscle (1). Here are some suggestions. Whey protein breaks down quicker than casein protein. Because of this, drinking it before a workout may be easier on the stomach. If you want to feel full longer, casein protein would be the way to go because it takes longer to digest. I'll drink whey protein before or after a workout (typically after). To get more protein at the end of the day, I'll drink casein protein because I won't go to bed feeling hungry. This is my personal preference. I do suggest to at least consume some form of protein and carbohydrate after a workout, whether it's whey or casein. If you don't know how much protein you need, click here.

Eat and drink your protein!

Resources

1. Willborn, C. D., Taylor, L. W., Outlaw, J., Williams, L., Campbell, B., Foster, C. A., . . . Hayward, S. (2013). The Effects of Pre- and Post-Exercise Whey vs. Casein Protein Consumption on Body Composition and Performance Measures in Collegiate Female Athletes. Journal of Sports and Medicine, 12, 74-79.

2. Devries, M. C., & Phillips, S. M. (2015). Supplemental Protein in Support of Muscle Mass and Health: Advantage Whey. Journal of Food Science, 80(S1). doi:10.1111/1750-3841.12802