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You can't expect wonders from protein supplements... no matter, when you take them, by the way. But I wouldn't mark them down as useless - even for rookies - based on the study at hand.

When I look at the 14 year old kids who need an written permission from their mum to train at the gym buying protein tons o powders and dozens of bars from the vending machines at the gym, even I have to shake my head. Not necessarily, because they're buying those products, but rather about what they tell each other about the effects: "Yo,... recently I ate this protein bar right after my workout and I felt swole for day..."

Now, you know that I am into supplement psychology and have no doubt about the fact that said kiddo felt swole all day, but we all know that protein is in no way a supplement the muscle-building and strength advantages of which will show within hours. And with that, I have a perfect transition to today's topic: The recent study from University of Central Florida in Orlando (Boone. 2015).
You will probably remember the most striking result of this study in which Carleigh H. Boone and colleagues "examine[d] the short-term effect of resistance training with and without protein supplementation on changes in muscle morphology and strength in untrained young men" (Boone. 2015).

Some of you may now be wondering: Why on earth do they even test that? We have ample evidence that protein supplements are powerful muscle builders! And you are right, but as it is the case for (almost) every research question in exercise science, even the highly acclaimed benefits of pre- or post-workout protein supplementation are somewhat contested. There's the evidence that supports the benefits of peri-workout protein supplementation on exercise induced muscle gains. Unfortunately, many of these studies may have been over-interpreted. Why?

FSR ≠ more muscle. Just because the post-exercise fractional protein synthesis increases this does not mean that you will gain more muscle in the long term. Check out this SV Classic to learn why!

Well, many of the often-cited studies in rookies, like Biolo et al. (1995), Phillips et al. (1997), or Tipton et al. (1999), measured increases in acute muscle protein synthesis and markers of anabolism. Due to their short design, however, increased long-term gains could only be predict, but not detect. In my 2014 article "Study Confirms: Acute Post-Exercise Myofibrillar Protein Synthesis Is Not Correlated with Resistance Training-Induced Muscle Hypertrophy in Young Men" (read more) you have learned, though, that the assumption that significant increases in post-workout muscle protein synthesis will necessary lead to significant augmented increases in muscle size in the long run is logical. but futile.

There are studies where this is the case, e.g. Coburn et al. (2006); Hulmi et al. (2010); Walker et al. (2009); Willoughby et al. (2007) - in both, trained and untrained individuals, but as Boone et al. rightly point out, there are also studies by Antonio et al. (2000) or Hoffman et al. (2009) in which protein or amino acid supplements had no beneficial effects on muscle or strength gains in either or trained and untrained individuals. The randomized, double-blinded study Boone et al. (2015) conducted is thus by no means superfluous. It is yet no perfect either, because with a length of only our week, the scientists picked exactly the time-frame in which things, or I should say "gains" happen faster than you can measure them. Furthermore, the use o a lower body unilateral resistance training makes it very difficult to infer the effects of protein supplementation on (a) muscle morphology [cross-sectional area, muscle thickness, pennation angle], (b) lower body power output, (c) maximal dynamic strength, and (d) maximal isometric strength in other muscle groups and in response to an overall metabolically more demanding workout.

Is it really bad to drink that whey shake before you eat the bananas, strawberries and blueberries, because whey makes you insulin resistant? Sounds "bogussy" and a closer look at the questionable methodological choices of the scientists who conducted the study don't make the results sign. more credible.

In the fitness community, whey protein is the #1 on the "must have supplement" list. Multi-vitamins? Creatine? Who cares, as long as you get your 30g of whey per day, you're good... really? One of you recently send me a study that would suggest that "good" is not exactly the right word to describe the effects of whey protein on at least one out of the set of well-established parameters of optimal metabolic health: Your muscles' insulin sensitivity.

In the paper that has been published in the reputable scientific journal "Diabetes", Gordon I. Smith and colleagues describe an experiment the results of which clearly suggest that whey doesed at 0.6g/kg fat free mass has a sign. insulin-desensitizing effect in twenty-two sedentary (<1.5 hour of exercise/w) and weight-stable (<2 kg change for at least 6 months), 50-65y old postmenopausal women who participated in this acute response study.
Acute response? Yes, there it is, the first in a line of problems that reduces the significance of the results. After all, testing the acute response to a certain health cannot tell you anything about the long-term effects on said parameter... especially if your subject group due to being sedentary and in an age where the parameter in question is deteriorating, anyway.

But let's not be the "it's not bros, so it's not valid for bros"-guys. Let's rather take a look at (a) the procedures and (b) the results and make up our minds later. And let's first take a look at a handful of important parameters of the study design: To determine the insulin sensitivity, the scientists used two hyperinsulinemic-euglycemic clamp sessions with the subjects being randomly assigned to do the procedure with vs. without whey protein first.

If you've got brawn and brain you cannot ignore that whey is much more than a potent muscle builder | learn more

"Before each clamp procedure, subjects were instructed to adhere to their usual diet and to refrain from vigorous physical activities for three days. Subjects were admitted to the Clinical Research Unit in the late afternoon, where they consumed a standard dinner between 1800 and 1900 h, and then fasted, except for water, until the next morning. At 0600 h, a catheter was inserted into an arm vein for the infusion of a stable isotope labeled glucose tracer; catheters for blood sampling were inserted into the radial artery of the opposite arm and in retrograde fashion into the femoral vein of one leg. At ~0645 h, a primed, constant infusion of [6,6- 2 H2]glucose (priming dose: 22 µmol·kg body wt-1, infusion rate: 0.22 µmol·kg body wt-1·min-1), purchased from Cambridge Isotope Laboratories Inc. (Andover, MA), was started and 4 h later the hyperinsulinemic-euglycemic clamp procedure was initiated with two 5-minute priming doses (first 200 mU·m-2 body surface area (BSA)·min-1 then 100 mU·m-2 BSA·min-1) of human insulin (Novolin R, Novo Nordisk, Princeton, NJ); for the remaining 230 min, insulin was infused at a rate of 50 mU·m-2 BSA·min-1. Euglycemia (at blood glucose concentration ~5.6 mM) was maintained by variable rate infusion of 20% dextrose (Baxter, Deerfield, IL) enriched to 2.5% with [6,6-2H2]glucose" ().

During the "whey trials", the subjects consumed 0.6 g of whey protein (unflavored Unjury®, ProSynthesis Laboratories, Inc, Reston, VA) per kg FFM dissolved in 360 ml water or the same volume of water alone. In addition, the researchers conducted a trial in which the subjects consumed the same amount of leucine.
To figure out if any effect they would observe was induced by whey, i.e. a complex protein, or just the most-applauded whey ingredient, i.e. leucine, the scientists ran a follow-up test (1-4 weeks later) in which the subjects consumed either 0.0684 g/kg FFM of pure leucine (that's equivalent to the amount of leucine in the whey protein)  dissolved in 360 ml Kool-Aid® (Kraft 94 Foods, Inc, Northfield, IL) or the same volume of the Kool-Aid® solution alone during the clamp procedure. I don't have to tell you that this was a mistake that makes the results of this follow-up useless for comparisons to the previous trial, in which the whey protein was mixed with water - Kool-Aid is after all all-carbohydrate - with 0.9g carbohydrates per ml of junk... ah, I mean per ml of the soft-drink.

Figure 1: Clearance of glucose during the hyperinsulemic clamp for the whole body and the legs (Smith. 2015). It is noteworthy that there control vs. active treatment signalling protein response (mTOR, p-AKT, ACC, etc. - not shown in figure) did not show differences that could explain the alleged negative effects of whey on glucose uptake (see Figure 2).

This does not mean that we couldn't use the data from the leucine trial, at all, though. But let's be honest, who cares about the non-significance of the effects of a non-gluconeogenic amino acid (meaning that leucine cannot be converted to glucose by the liver) if you cannot compare them to the significant decrease in insulin-mediated glucose disposal (38.8 vs 51.9 µmol glucose per µU insulin/ml / min; P<0.01) the scientists observed in the whey condition, because the test was messed due to the use of a different and by no means "neutral" control?

Figure 2: Don't worry, while the scientists cleverly call the glucose disappearance into the legs "leg glucose uptake" it's just the product of blood flow to the legs times whole body glucose disposal and suffers from the same methodological short-come as the whole body glucose disposal that assumes that whey was non-gluconeogenic (data from Smith. 2015)

Rather than as a basis to argue that whey is bad and leucine is good, you can use the Kool-Aid glitch and the fact that leucine cannot be converted to glucose in the liver to substantiate the following hypothesis: If the scientists had accounted for the gluconeogenic glucose load from whey when they tested their allegedly sugar-free (manufacturer claim) whey protein vs. water in the previous trial, they would probably have found no significant effect of whey protein on muscular glucose uptake, because the test wouldn't have been unfairly thwarted in favor of the water control which came without the additional glucose load from the whey-induced gluconeogenesis in the liver.

Figure 3: Both, acute and chronic realistic and thus relevant studies show beneficial effects of whey on glycemia (Petersen. 2009) and insulin sensitivity (Pal. 2010) - you decide which studies to trust ;-)

Plus, even if we assume that this hypothesis wasn't true (I am pretty convinced it is), the results of the study at hand would still be an inexplicable artifice that stands in stark contrast to the well-proven multi-facetted acute and chronic beneficial effects of whey protein on glucose- and weight-management in healthy, diabetic and pre-diabetic individuals (Layman. 2004; Frid. 2005; Peterson. 2009; Akhavan. 2010; Pal. 2010) - effects of which no one ever claimed that they were mediated by acute increases in muscular insulin sensitivity, by the way; and that despite the fact that the data from Pal (Figure 3, left) clearly indicates that these benefits occur in the real world.

References:

• Akhavan, Tina, et al. "Effect of premeal consumption of whey protein and its hydrolysate on food intake and postmeal glycemia and insulin responses in young adults." The American journal of clinical nutrition 91.4 (2010): 966-975.
• Frid, Anders H., et al. "Effect of whey on blood glucose and insulin responses to composite breakfast and lunch meals in type 2 diabetic subjects." The American journal of clinical nutrition 82.1 (2005): 69-75.
• Layman, Donald K., and Jamie I. Baum. "Dietary protein impact on glycemic control during weight loss." The Journal of nutrition 134.4 (2004): 968S-973S.
• Morifuji, Masashi, et al. "Dietary whey protein increases liver and skeletal muscle glycogen levels in exercise-trained rats." British journal of nutrition 93.04 (2005): 439-445.
• Pal, Sebely, Vanessa Ellis, and Satvinder Dhaliwal. "Effects of whey protein isolate on body composition, lipids, insulin and glucose in overweight and obese individuals." British journal of nutrition 104.05 (2010): 716-723.
• Petersen, Brent L., et al. "A whey protein supplement decreases post-prandial glycemia." Nutr J 8.47 (2009): 1475-2891.
• Smith, Gordon I., et al. "Protein ingestion induces muscle insulin resistance independent of leucine-mediated mTOR activation." Diabetes 64.5 (2015): 1555-1563.