For instance, a recent study compared the effect of taking whey protein or its hydrolysate before a meal on food intake, premeal and postmeal satiety and concentrations of blood glucose and insulin in healthy young adults. Two randomized crossover studies were conducted. Ten to 40 grams of whey protein mixed in water was provided in experiment 1, and either five to 40 grams of whey protein or 10 grams of WPH were provided in experiment 2. Thirty minutes afterward the subjects in experiment 1 were fed a pizza meal at which they could eat as much as they wanted, and those in experiment 2 got a pizza meal limited in calories. Sounds like a college student’s dream—free pizza and some whey protein! In experiment 1, whey protein suppressed food intake and reduced postmeal blood glucose concentrations. In experiment 2, whey protein, but not whey protein hydrolysate, was found to reduce postmeal blood glucose and insulin in a dose-dependent manner.
So what does all that mean? Whey protein taken before a meal reduces food intake, postmeal blood glucose and insulin.1 So if staving off hunger is key, then choose intact whey over whey protein hydrolysate.
Another study compared the effect of dietary protein type on glycogen in the postexercise phase in rats.2 Several groups of rats were subjected to glycogen-depleting exercise, including a control group that received no supplement. The other groups were given either glucose or glucose plus whey protein, whey protein hydrolysate, casein hydrolysates or a branched-chain amino acid solution. Two hours later, postmortem excision of the triceps muscles of all the rats took place, and skeletal-muscle glycogen was measured. Whey protein hydrolysate caused significant increases in skeletal muscle glycogen, compared with the other substances.
Moving on. What happens when you compare whey protein hydrolysate to whey protein isolate? In a double-blind randomized parallel trial, 28 sedentary males took 25 grams of whey protein isolate or whey protein hydrolysate after heavy exercise.3 Researchers found that the latter was better at assisting athletes in recovering from fatiguing eccentric exercise.
So here’s the lowdown: Taking in whole whey is great for suppressing appetite. Whey protein hydrolysate is likely best for recovering from exercise and for muscle glycogen restoration. My advice: Take a whey protein hydrolysate supplement postexercise. During the day have a whey-based shake to stave off hunger and to further improve the body’s anabolic environment.
Editor’s note: Jose Antonio, Ph.D., is the CEO of the International Society of Sports Nutrition (www.TheISSN.org); also check out his site www.TheWeekendWorkout.com.
1 Akhavan, T., et al. (2010). Effect of premeal consumption of whey protein and its hydrolysate on food intake and postmeal glycemia and insulin responses in young adults. Am J Clin Nutr. 91 (4):966-75.
2 Morifuji, M., et al. (2010). Postexercise carbohydrate plus whey protein hydrolysates supplementation increases skeletal muscle glycogen level in rats. Amino Acids. 38(4):1109-15.
3 Buckley, J.D., et al. (2010). Supplementation with a whey protein hydrolysate enhances recovery of muscle force-generating capacity following eccentric exercise. J Sci Med Sport. 13(1):178-81.