The Thrilla in Manila
By Jose Antonio Ph.D.

If you’re an old fight fan like I am, you probably remember the epic boxing match between Joe Frazier and Muhammad Ali in their last of 3 fights. Ali squeezed out a victory and nailed his reputation as the greatest boxer of all times. Period. When it comes to the battle of proteins, it seems that the “Ali versus Frazier” equivalent is whey versus casein. The initial comparison was a study that looked at the acute or short term effects of whey versus casein. They found that net leucine balance, a measure of possible gains in muscle protein, over the 7 hour period after the meal was more positive with casein than whey.(1) But again, that was a short-term feeding study. What happens when you take the stuff for weeks? Well, the story seems a bit different. Certainly, we do know that different dietary proteins affect whole body protein anabolism and accretion. Thus, scientists looked at whey versus casein supplementation during a 10 week, supervised resistance training program. In a double-blind protocol, 13 male, recreational bodybuilders supplemented their normal diet with either whey isolate or casein (1.5 gm/kg body wt/d which is equal to 136 grams of protein for a 200 lb individual) for the duration of the program. Strength was assessed by 1-RM in three exercises (barbell bench press, squat, and cable pull-down). Body composition was measured by dual energy X-ray absorptiometry. Plasma glutamine levels were also determined. All assessments occurred in the week before and the week following 10 wk of training. Plasma glutamine levels did not change in either supplement group following the intervention. However, the whey isolate group gained more lean mass than the casein group (5.0 versus 0.8 kg for whey and casein, respectively). Also, the whey group had a significant decrease in fat mass (-1.5 kg) compared to the casein group (+0.2 kg). And to top it off, the whey isolate group also significantly stronger in all measures! And when the strength changes were expressed relative to body weight, the whey isolate group still achieved significantly greater improvements in strength compared to the casein group.(2)

Clearly, it’s one thing to compare how proteins ‘work’ over 7 hours. But it is immensely more important to see what they do over weeks and months. If you consume only whey or casein, whey is clearly a great protein. But you can’t go wrong with casein either. It is a ‘slow’ protein that’s ideal for a ‘bedtime’ protein or if taken in combination with whey. So for your best bet, take a combination of whey and casein post-workout (I’d say 80% whey, 20% casein). And 1 hour before you go to bed, do the opposite (80% casein, 20% whey).

References
1. Boirie Y, Dangin M, Gachon P, Vasson MP, Maubois JL, Beaufrere B. Slow and fast dietary proteins differently modulate postprandial protein accretion. Proc Natl Acad Sci U S A 1997;94:14930-5.
2. Cribb PJ, Williams AD, Carey MF, Hayes A. The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine. Int J Sport Nutr Exerc Metab 2006;16:494-509.

 

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