Western vs. Ketogenic Diet - Greater 'Gains' Materialize Only After Glycogen-Loading in 12-Wk Study in Trained Subjects

Unfortunately, I cannot tell you if the "Western" diet was also full of junk food. I just know that its 20/55/20 ratio of PRO/CHO/FAT is everything but ideal for one's body composition.

While it has not officially been published, yet, I am pretty sure that Jacob M. Wilson's latest paper is going to be one of the most-downloaded articles in the upcoming issue of the Journal of Strength and Conditioning Research it's about to be published in. You're asking yourself why I am so sure about that? Well, it's already the most-discussed ahead-of-print article in months (see any Facebook Fitness / Exercise Research group or bulletin board), because it claims to confirm that ketogenic diets "can be used in combination with resistance training to cause favorable changes in body composition, performance and hormonal profiles in resistance-trained males" (Wilson 2017) - a claim that gets both ketophiles and keto-haters absolutely fired up.
Before I will delve into a brief discussion of what the study is actually about, I would like to point outu that I have revised the original draft several times - both, to incorporate/answer questions that I've found online and in response to a brief conversation with the authors, who were by no means the first to "examine resistance training adaptations using a human model" (Wilson 2017). What Wilson et al. can boast of, though, is that their paper is the first to address the issue using a decently realistic resistance training program in healthy, previously trained young men. A scenario in which the authors hypothesized a priori that ...

"the KD [ketogenic diet group] would decrease body fat to a greater extent than a WD [western diet] group, while maintaining skeletal muscle hypertrophy, strength, and power" (Wilson 2017).  

In that, the effects of the heavily criticized glycogen load you may have read about elsewhere, was not a means to make this hypothesis come true, but an effort to generate a level playing field of which the authors write that it also constitutes a "tertiary purpose" of the study, which was thus also intended as a means to investigate "the effects of carbohydrate refeeding following KD adaptation on body composition and performance" (ibid.)

The glycogen loading was not meant to skew, but to create a level playing field.

Unfortunately, this strategy backfired in a way that's currently getting people all over the interwebs so "excited" (to say the least) that they focus exclusively on this failed attempt to compensate for the glycogen advantage and do not acknowledge the strengths of the study.
Strengths such as (1) the selection of trained subjects and exclusion of those with a squat performance that was significantly below 1.5 times the subjects' own body weight (here we have one of the criticized issues with the reporting, though, because the value Wilson et al. provide is 1.56 ± 0.14 and thus below 1.5 if you subtract the standard deviation from the arithmetic mean), as well as the prescription of (2) a realistic resistance training routine with a hypertrophy focus (see Table 1).

Table 1: Training protocol; *rest was 60-90 seconds on hypertrophy days and 3-5 minutes on strength days (Wilson 2017).

Extra cardio or other endurance training and/or other athletic activity outside of the three weekly workouts was strictly prohibited. All exercises were either performed for the given number of reps or to failure. The load utilized for weeks 3-6 ranged from 65 to 95 % of subjects’ initial 1RM. However, these loads were increased by 2-5 % for the final 7-9 weeks of training depending on subject’s ability to perform the prescribed repetitions during weeks 3-6.

Figure 1: Visualization of the macronutrient composition of the diets (Wilson 2017).

As the authors explain, the "subjects tapered by decreasing volume by 40-50 % through decreasing sets on auxiliary lifts on Monday and Wednesdays and only performing 1RM testing on Fridays" (Wilson 2017) in the final two weeks of the study period, of which it may be worth mentioning that it lasted 12 weeks: a two-week lead-in, 9 weeks until the highly debated glycogen repletion protocol began and another week until the final measurements of exercise performance and body composition.
Dietwise, the subjects, N=25 resistance-trained males who had an average max squat performance of 1.56 ± 0.14 times their body weight and an average of 5.5 ± 3.8 years of training experience, were randomly assigned to...

• Only recently scientists have been able to show that coffee can kickstart ketosis, even if you eat a sign. number of carbs for breakfast | learn more.

  the WD = western diet - 20% calories from protein, 55% from total carbohydrate, and 25% from fat
• the KD = ketogenic diet - 20% calories from protein, 5% from carbohydrate including fiber, and 75% from fat 
• in both groups, subjects were instructed to consume food immediately following training that contained a minimum of 20-30g of protein, with the remainder of the meal reflecting the accurate ratios prescribed throughout the day

The individual energy content was calculated based on maintenance calories determined by the Mifflin St. Jeor equation. Now, while this is standard procedure in metabolic research it is still problematic, as the equation can be 15% off the actual requirements. Accordingly, it is not clear, whether the subjects were in a caloric deficit. Since this holds true for both groups and the overall energy intake was identical in both groups, though, this is not relevant to the study's original research goal, which is to determine differences between a ketogenic and a western diet.

Excellent dietary adherence and full ketosis in the main part of the study

What we can tell, though, is that the subjects' adherence to the diets was excellent (2608.6 ± 157.5kcal/day vs.  2549.5 ± 212.5 kcal/day,  217.02 ± 15.5 g fat per day vs.  83.4 ± 13.3 g fat/day, 133.6 ± 10.8 g protein per day vs. 132.2 ± 13.3 g protein per day, 30.9 ± 5.9 g carbohydrates per day vs. 317.6 ± 31.1 g carbohydrates per day in the KD vs. WD group, respectively) and confirmed by both both food logs and weekly urinary ketone measurements.
The last-mentioned ketone tests confirmed that all subjects in the ketogenic dieting group (KD) had reached full ketosis at the beginning of the 2nd week of the two-week lead-in - an important observation that was not made (either because it was not tested or because the high protein content of the diet allow the subjects to reach full ketosis) in some previous "low carbohydrate diet"-studies.

Figure 2: Changes in body composition (in the given timeframe in kg) according to DXA scans (Wilson 2017).

So far, so good... I guess, it's about time to address the catch, then: Before the final DXA scans (results see Figure 2), muscle circumference and strength tests were done, the subjects in the KD group were subjected to a classic glycogen loading protocol consisting of two days on 1g/kg carbohydrates, followed by two days on 2g/kg carbohydrates and 3g/kg carbohydrates in the last 2 days before the DXA scan - obviously, with an isocaloric decrease in dietary fat that maintained the caloric intake at the previously described calculated maximum.

Hindsight is easier than foresight: If you glycogen-load, it'd be logical to do so in both groups

In general, there's nothing wrong about this. To create a truly equal playing field, however, it would yet have been smarter to either glycogen-load (or, alternatively, -deplete) both groups. With only one group getting the extra boost in muscle fullness, however, the DXA data from week 11 is as skewed (albeit into the other direction) as the measures that were taken in week 10, when the emptied glycogen stores in the KD group gave the similarly elusive impression that the consumption of a ketogenic diet had impaired the subjects' lean mass gains while extremely augmenting their fat loss.
If we assume that the effects of the loading protocol were similar to those Bone et al. (2016) observed with an almost identical protocol in their recent study (see discussion in the red box, above), the extra glycogen would appear as a ~3% increase in lean mass on the DXA scans - and that's pretty much what we see in the study at hand. Accordingly, the "real" muscle gains in the KD group are probably somewhere in-between what we see in Figure 2 (left) for the 1-10 wk and 1-11 wk period. This, however, would imply that the "real" lean mass gains (and the increase in muscle thickness, see Figure 3) over the course of the study would - within the usual statistical margins of error - be identical for both diets.

It's not true that Wilson et al. do not address the issue of glycogen-driven 'extra gains'
In view of the harsh criticism Wilson et al. have received over the Easter weekend, it should be mentioned that the authors come to a very similar conclusion (without, however, citing the study Bone et al.), when they write in the discussion of their results that "the abrupt, yet not unexpected, changes in LBM were primarily driven by drastic changes in water flux during the last week of the study" (Wilson 2017) - and conclude, just as I did, that both "groups gained similar amounts of muscle mass throughout the entire study" (ibid.).

Figure 3: Rel. changes (%) in muscle thickness and performance data from week 1-10 and 1-11 (left) and absolute DXA data with lean mass at the top and fat mass at the bottom (full bars = KD, open bars = WD | Wilson 2017).

The fact that the authors do not make this more explicit in the abstract and, even more importantly, speak of a body composition "advantage" for the KD diet in the "practical implications" section of the paper, is in fact reason for warranted criticism. After all, the alleged improvements in fat loss vanish just as the increases in lean body mass did, if we subtract the ~6% "virtual" loss of body fat Bone et al. observed as a result of glycogen depletion, alone, and/or estimate the "real" body fat loss by averaging over the fat mass Wilson et al. measured in week 10 and 11, respectively.

If there's no inter-group difference, the study at hand still shows just what the first part of the conclusion of the abstract says: "The KD can be used in combination with resistance training to cause favorable changes in body composition, [and] performance" (Wilson 2017).

So, even if we assume that the extra gains were an experimental artifice and assume that a potential fat loss advantage did not exist, we should at least be able to agree that the study at hand confirms, irrespective of its methodological problems and 'suboptimal' reporting of the results, that ketogenic diets can build the same amount of lean mass and strip the same amount of fat off the bodies of trained young men, when all other parameters are kept equal. Whether the "western diet", a high carb, lowish protein, medium fat diet, is an adequate yardstick when it comes to the question "What's the best diet for gymrats, physique athletes and/or bodybuilders?", however, is yet another story.
References:

• Ball, Thomas C., et al. "Periodic carbohydrate replacement during 50 min of high-intensity cycling improves subsequent sprint performance." International Journal of Sport Nutrition 5.2 (1995): 151-158.
• Bartlett, Jonathan D., John A. Hawley, and James P. Morton. "Carbohydrate availability and exercise training adaptation: too much of a good thing?." European journal of sport science 15.1 (2015): 3-12.
• Bone, Julia L., et al. "Manipulation of Muscle Creatine and Glycogen Changes DXA Estimates of Body Composition." Medicine and science in sports and exercise (2016).
• Burke, Louise M., et al. "Low Carbohydrate, High Fat diet impairs exercise economy and negates the performance benefit from intensified training in elite race walkers." The Journal of Physiology (2017).
• Cox, Pete J., et al. "Nutritional ketosis alters fuel preference and thereby endurance performance in athletes." Cell Metabolism 24.2 (2016): 256-268.
• Gore, Christopher J., et al. "Live high: train low increases muscle buffer capacity and submaximal cycling efficiency." Acta physiologica scandinavica 173.3 (2001): 275-286.
• Jabekk, Pal T., et al. "Resistance training in overweight women on a ketogenic diet conserved lean body mass while reducing body fat." Nutrition & metabolism 7.1 (2010): 17.
• Paoli, Antonio, et al. "Ketogenic diet does not affect strength performance in elite artistic gymnasts." Journal of the International Society of Sports Nutrition 9.1 (2012): 34.
• Roberts, Michael D., et al. "A putative low-carbohydrate ketogenic diet elicits mild nutritional ketosis but does not impair the acute or chronic hypertrophic responses to resistance exercise in rodents." Journal of Applied Physiology 120.10 (2016): 1173-1185.
• Wilson et al. "The Effects of Ketogenic Dieting on Body Composition, Strength, Power, and Hormonal Profiles in Resistance Training Males." J Strength Cond Res. 2017 Apr 7. doi: 10.1519/JSC.0000000000001935. [Epub ahead of print]