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Best Post-Workout Protein Milkshakes? Whey and Casein Combo

Imagine a sponge wrung completely dry sitting next to a sink full of water. A simple dunk of that dry sponge and instantly it will fill and expand with every spongy fiber with water becoming heavy and overflowing with it. This is a great picture of your muscles and their receptivity after a hard work out. Simply put this is one of the most important moments to provide your body with protein. A balanced post-workout protein milkshake can dramatically impact progress and recovery.

Post-workout milkshakes should also consist of a percentage of simple carbs to better the total uptake of protein and replenish glycogen that was expended during the workout. Again like that dry sponge, if you fill your body with the important nutrients it needs immediately after the workout, you literally accelerate the process of repairing the muscle cells and re-synthesizing muscle glycogen. Because your muscles are so depleted they will suck those nutrients right up like a vacuum and you and your body will better for it!

In a 2006 study conducted at Baylor University, researchers concluded that the best post-workout milkshakes contains a mixture of both fast and slow proteins.

The study consisted of 36 men, whose ages ranged between 23 and 29, who did weight training for 10 weeks. Prior to this 10 week study the participants had all been weight training for at least a year on their own. Each were given the same training schedule to follow that consisted of training 4 times a week targeting all of the large muscle groups in the body in 2 sessions. The subjects did a range of sets starting with 10 reps and ending with sets of 6 reps.

The studies protein milkshake variables consisted of:

  • a placebo group drank a shake that contained only carbohydrates. {P}
  • One control group drank a protein milkshake containing 40 g whey protein, 5 g glutamine and 3 g BCAAs. {WGB}
  • A second control group drank a protein milkshake containing 40 g whey protein, 8 g casein. {WC}
  • The three shakes all contained the same amount of energy.

On non-training days, the study subjects consumed the protein milkshake in the morning. On training days they drank a protein milkshake as soon as possible after finishing the workout ended and never more than 2 hours after training was over.


After 10 weeks the WC group had progressed more than the other groups on all counts. The studies scientist’s and researcher’s concluded that  “protein supplementation is effective at promoting increases in fat-free mass and muscle endurance…and a combination of whey protein and casein protein appears to be more effective at promoting gains in fat-free mass.”

Sources sited: Journal of Strength and Conditioning Research, 2006, 20(3), 643–653 2006 National Strength & Conditioning Association