Soy protein is like the Tyler Perry movie of the protein world. You can't get away from the stuff no matter how hard you try. And there's a reason it is getting jammed down our throats. There are currently close to 78 million acres of farmland that are growing soy in the U.S. If soy protein is so popular, maybe you should use some for your post-workout recovery drink? Or, maybe not. Two of the most respected researchers in the sports nutrition world, recently completed a study to find which type of protein (whey or soy) imparts the superior muscle-building benefit. Scientists Jeff Volek and William Kraemer (who are like the Batman and Sherlock Holmes of supplement research, but cooler,) took 63 men and women between the ages of 18 and 35 and put them on a nine-month weightlifting program. One group was given a post-training shake that consisted of only carbs, a second group was given 22 grams of soy protein, and the third (and luckiest) group was given 22 grams of whey protein concentrate. All groups trained two to three times per week and consumed their shake on non-training days as well. At the end of nine months, the whey protein group had added 7.3 pounds of muscle, while the soy group added less than four pounds. Even the carb-only group did better than those poor soy suckers, acquiring five new pounds of muscle over the course of the experiment. Volek and Kraemer surmise that whey's superior leucine content is the reason that whey is so much more effective. There was a correlation between the whey-drinkers who built the most muscle and those who had the highest concentrations of the leucine in their blood. Undoubtedly, the daily use of whey (even on non-training days) contributed to the increased leucine levels. (Incidentally, Scivation XTEND contains 3.5 grams of leucine per serving.) If your goal is to add muscle (and whose isn't?) it seems that a quality protein, such as Scivation Whey, is an absolute necessity to a smart muscle-building program.