Effect of resistance training and whey on body composition

The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine.

Different dietary proteins affect whole body protein anabolism and accretion and therefore, have the potential to influence results obtained from resistance training. This study examined the effects of supplementation with two proteins, hydrolyzed whey isolate (WI) and casein (C), on strength, body composition, and plasma glutamine levels during a 10 wk, supervised resistance training program. In a double-blind protocol, 13 male, recreational bodybuilders supplemented their normal diet with either WI or C (1.5 gm/kg body wt/d) 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 assessed by dual energy X-ray absorptiometry. Plasma glutamine levels were determined by the enzymatic method with spectrophotometric detection. 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. The WI group achieved a significantly greater gain (P < 0.01) in lean mass than the C group (5.0 +/- 0.3 vs. 0.8 +/- 0.4 kg for WI and C, respectively) and a significant (P < 0.05) change in fat mass (-1.5 +/- 0.5 kg) compared to the C group (+0.2 +/- 0.3 kg). The WI group also achieved significantly greater (P < 0.05) improvements in strength compared to the C group in each assessment of strength. When the strength changes were expressed relative to body weight, the WI group still achieved significantly greater (P < 0.05) improvements in strength compared to the C group.

Full paper here, well worth reading. The whey group gained 5 kg lean mass (!) and lost 1.5 kg fat. These were not novice bodybuilders either, which is usually the case when you see huge effects like this.


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1 comment
DdR says November 26, 2013

Interesting study. And here I was thinking I was doing my body good by consuming a milk-heavy shake with whey. I guess I can forego the milk from now on.

Just make sure that the reader understands that the researchers used hydrolyzed whey, and not whey protein isolate. They are two different proteins. The former is short-chained, quickly absorbed by your muscles, and very bitter. The latter is longer-chained, has a ton of glutathione and is not as quickly absorbed, but is not bitter.

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