Significant Weight Gain W/ Whey vs. Casein?! Anabolism / Muscle-Protection or Fat Gain Despite Hitting the Weights?

While being misinterpreted as an "anti-whey" study by one of you, the latest whey as your main protein source study from Brazil only adds to the evidence that there's something special about whey.

One thing I like about writing this blog is that I have a lot of contact to you, the readers. One of you recently sent me the link to a study from the University of Ouro Preto in which the authors report what he called a "disconcerting" weight gain when exercise and weight training were combined. A closer look at the study reveals, however, that this "disconcerting" weight gain (even though that is not totally obvious) is probably good news.

But before we get to the implications and interpretations, let's first take a look at what the scientists did and what they observed. You'll see that this is of paramount importance wrt to not misinterpreting the weight gain in Figure 1.

Note that the study at hand is not about High-protein diets - with 14% some may call it deficient

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Being aware that whey protein (WP) is known for its nutritional value and antioxidant properties, the authors speculated that the latter, or rather the protective effect they would have on the muscle tissue, would be another important contributor to Wheys beneficial effects on skeletal muscle development.

To test their hypothesis that a reduced muscle damage and thus reduced effort to rebuild the broken tissue before accumulating new muscle would contribute to the muscle building effects of whey protein in resistance training individuals, the authors used a model study: in thirty-two male Fischer rats who were randomly assigned to control sedentary, control exercised, whey protein sedentary, and WP exercised groups (n=8/group), half of the rodents (those in the exercise group) were subjected to an interesting resistance training regimen:

"RE consisted of inducing the animals to perform sets of jumps in a circular plastic container with a depth corresponding to 150 % of their body length. Weights were attached to the animal’s chest to promote submersion and the resistance to the exercise. When the rats touched the bottom of the container, they had to jump to emerge from the water to breathe. The RE program consisted of inducing the animals to perform four sets of 10 jumps per day, five times per week for 8 weeks. A one-minute rest interval was included between each set of jumps. Exercise intensity was increased weekly by changing the maximum weight supported by each animal to perform the set of jumps correctly (~25 % of body weight in week 1, ~30 % in week 2, ~ 35 % in week 3, ~40 % in week 4, ~45 % in week 5, ~50 % in week 6, and ~ 55 % in weeks 7 and 8); 55 % of body weight was the greatest weight supported by the rats to perform all jumping sets correctly" (Teixeira. 2016)

Now, what is particularly interesting about the study is that the researchers did not add the whey protein to the diet, but simply replaced the regular 14% protein in form of caseinate in the rats' AIN-93M chow with whey protein (still only 14% of the energy).

Why is it important that the scientists replaced the protein source? If Teixeira et al. had simply added extra-whey on top, you could always have argued that the effects they observed would have been the mere result of extra protein, not some special quality (in this case most likely the antioxidant effects) of whey.

Against that background, it is quite interesting to see how significant the effect of whey turned out to be... at least in the exercised group, where you can easily see in Figure 1 that the initially identical weights differed significantly at the end of the 8-week study. Since differences occurred only in comparison to the control + exercise group and we don't have total lean and fat mass data, it is, unfortunately, impossible to tell for sure how much if any of the gained weight was, as the previously mentioned SuppVersity reader feared body fat and how much was muscle weight.

Figure 1: Yes, for sure - at first sight, this logs bad for whey and good for the low-protein AIN-93M standard diet (Teixeira. 2016); I mean, the rats gained the least weight? Well, that's one of the common misunderstandings I had in mind when I started the SuppVersity. Science is not always as straight-forward as you think. So read the rest of the article before you freak out or argue that "this is just because it's rodents" - that's pathetic, anyway).

What we can say for sure, is that the exercise regimen triggered significant muscle-specific mass reductions (in gains), unless its negative effects on the rodents muscle was buffered by the pro-anabolic and anti-oxidant effects of whey protein (see Figure 2, where the %-ages over the bars in the "muscle weight (g)" columns indicate the difference between sedentary control and the rodents who did the jumps for 8 weeks).

Figure 2: Changes in body weight (%-ages indicate relative weight change from baseline), muscle weight and food intake (%-ages indicate difference between exercise and control group | Teixeira. 2016)

Accordingly, it would be wrong to use the study at hand to make a case against whey protein and to call it an obesogen, i.e. another of the many foods that contributing not just to weight, but also and maybe even specifically to fat gain - in spite of full commitment (the rodents obviously had no choice, which is a clear strength of the often criticized rodent studies) to a rather intense exercise regimen (see previous quote).

So, if it's not the "disconcerting news" that whey could make you fat and/or blunt weight loss what is it, then, that the study at hand tells us. Well, I guess there are two answers: Answer (a) is a confirmation of the authors' hypothesis that whey protein has significant antioxidant and anticatabolic effects. Answer (b), on the other hand, is not as favorable for whey protein is (a) as it emphasizes that, without exercise, simply adding whey protein to the diet won't build any extra muscle... speaking of muscle, I've communicated with the authors who confirmed that they "did not evaluate body composition in these rats" (so it's not that they just didn't report it, because it may not be that relevant for their specific study interest), but found "that WP exercised rats showed a better body composition and exercise performance" (private communication); and, what's more, to quantify the last-mentioned effects, will be the goal of follow-up studies.

But what about body com-position? As explained in this bottom line, an assessment of the body composition was beyond the scope of the study at hand. Luckily, you can find evidence of whey's ability to and superiority in (a) augment/ing training-induced improvements in body comp (Hayes. 2008) and (b) po-sitively alter the body comp of free-living, untrained adults (Baer. 2011). This goes for both individuals healthy, but also and especially people who have issues with inflammation, like the overweight and obese subjects in Baer et al. (2011) who consumed 2x56 g/d of soy or whey protein for 23 weeks and saw gains in lean (+0.5 kg) and reductions in fat mass (-2.3kg) only with the latter, i.e. whey protein - not with the former, i.e. soy protein. Whether that's a result of superior or different antioxidant effects of whey vs. soy protein would need further studies, but in view of the results of the Teixeira study, it is at least not unlikely that the antioxidant prowess of whey protein (at least) partly explains its unique (vs. soy) beneficial effects in the Bear study, as well.

So, what can we really learn from this study? It's not just the "mouse or man problem" that limits the significance of the study at hand. In addition, you must not forget that weight gain (including body fat) is a mere necessity in a group of healthy growing young animals; and at the age of 60 of usually ~660 days (Chesky. 1976), the Fischer rats in Teixeira's experiment were just that: still growing.

Against that background, there's no reason to start being afraid of whey protein supplementation, because it promotes weight gain (it does ;-), but that's as the study at hand shows because "WP ingestion inhibited the oxidative effects induced by RE, including the downregulation of gene expression of glutathione system enzymes and phagocyte infiltration in gastrocnemius muscle cells" (Teixeira. 2016) and increased both body and muscle weight gain compared to exercise, alone.

The reasons you may rightly be not 100% happy with the Teixeira's latest study are thus not related to its outcome. Rather than that, it's a logical result of methodological issues that originate in the specific research focus of the paper at hand. With the goal being "to evaluate whether the antioxidant properties of WP could contribute to muscle weight gain in response to resistance exercise (RE)," (Teixeira. 2016) the potential role of fat gain is not even mentioned in the thesis statement. Accordingly, the scientists harvested 'only' the slow and fast twitch muscle fibers to measure potentially different muscle weight developments exemplarily in both, primarily aerobic and anaerobic muscle fibers. And the results confirmed what we tend to forget way too often: Whey is not 'just' a muscle builder, it's also a potent anti-inflammatory agent... but wait, you know that already if you've read my you have read my 2014 article "Whey Beyond Brawn: 10+ Things You Probably Didn't Know Whey Can Do for You" | Comment on Facebook!

References:

• Baer, David J., et al. "Whey protein but not soy protein supplementation alters body weight and composition in free-living overweight and obese adults." The Journal of nutrition 141.8 (2011): 1489-1494.
• Chesky, Jeffrey A., and Morris Rockstein. "Life span characteristics in the male Fischer rat." Experimental aging research 2.5 (1976): 399-407.
• Hayes, Alan, and Paul J. Cribb. "Effect of whey protein isolate on strength, body composition and muscle hypertrophy during resistance training." Current Opinion in Clinical Nutrition & Metabolic Care 11.1 (2008): 40-44.
• Teixeira, Kely R., et al. "Whey protein increases muscle weight gain through inhibition of oxidative effects induced by resistance exercise in rats." Nutrition Research (2016).