12-Week Study: 25g Bed-Time Protein Almost Doubles Size & Increases Strength Gains - Where's the Catch?

Fridge raiding allowed, no even suggested! At least if what you take out of the fridge is a chilled protein shake - preferably one with at least some slow-digesting casein.

You will remember my provocative claim that you can "Gain 3.2kg of Lean Mass Over Night" from a 2012 SuppVersity article (read it | Groen. 2012). The claim was based on an extrapolation of the lean mass gains you would see within one year if the only thing you did was to consume one serving of slow digesting protein before bed - no training, no other dietary intervention.

Now, three years later, I am happy to tell you my prediction was not too far off. In fact, the provision of a shake containing 27.5 g of protein, 15 g of carbohydrate, and 0.1 g of fat right before bed even doubled the gains of the those 22 young, recreational active, but non-resistance trained men who had been randomly assigned to the active treatment (the energy-free placebo tasted identical).
Needless to say that Tim Snijders and his colleagues had hypothesized that the provision of extra dietary protein before sleep would "further augment the gains in muscle mass, strength, and muscle fiber size during more prolonged resistance-type exercise training in healthy young men" (Snijders. 2015). That the extra-gains the subjects in the active group saw in response to 12-weeks of resistance training + supplementation would be that significant is yet something the scientists from the Maastricht University probably didn't expect, either.

Figure 1: Changes in cross sectional area and muscle size of type II fibers (Snijder. 2015).

Ok, the muscle diameter aka the "cross-sectional area" (CSA) increase of the quads in the PRO group was "onl" 75% not 100% higher and the whole body lean mass did not show a treatment effect (=similar increases in both groups), but the total change in 1RM of all strength tests, i.e. leg presses, extensions, chest press, shoulder press, horizontal row and vertical pull-down clearly confirm that the protein supplement did it job and it did it well (see Figure 2).

Figure 2: 1RM increased as well.

What we do have to keep in mind, though, is that the study participants did not, as most of you probably do, consume a protein shake right after their workouts. The addition of 25g of protein right before bed did thus increase the relative protein intake of the subjects in the PRO group by 0.6g/kg. The subjects in the PLA group, on the other hand, were stuck with their sufficient, but certainly not exuberant intake of 1.3g/kg body weight per day form dietary sources, a post-workout protein shake was not consumed by either of the two groups.

This does not negate the scientists' conclusion that "protein ingestion before sleep represents an effective dietary strategy to augment skeletal muscle mass and strength gains during prolonged resistance-type exercise training in healthy, young men." (Snijder. 2015), but it certainly raises the question if the differences would have been similarly pronounced if the protein intakes had been matched or if the scientist had compared post-workout vs. pre-bed consumption.
References:

• Groen, Bart, et al. "Protein ingestion before sleep improves postexercise overnight recovery." Medicine and science in sports and exercise 44.8 (2012): 1560-1569.
• Snijders, et al. "Protein Ingestion before Sleep Increases Muscle Mass and Strength Gains during Prolonged Resistance-Type Exercise Training in Healthy Young Men." The Journal of Nutrition (2015): Ahead of print.