|I don't know what exactly was in the ketogenic rodent chow that was used in the study at hand, but I doubt it were transfat laden sausages ;-)|
Yes, you heard me right. There is new research on ketogenic diets that does not focus on weight loss, the obese and/or cancer. Rather than that, the studies discussed in this installment of the ISSN '15 Research Review deal with the effects of ketogenic diets on the skeletal muscle anabolic response to resistance exercise, as well as its effects on weight gain in an ad-libitum diet scenario.
- You can build muscle on a ketogenic diet - theoretically -- While previous studies on low carbohydrate diets have already demonstrated that eating tons of fat and almost no carbohydrates can trigger improvements in body composition, it is still not clear whether the consumption of virtually carbohydrate-free diets may impair the resistance training induced anabolic response in skeletal muscle. In a previous ISSN article, for example, Paoli et al. )2012) state that their observations in gymnasts on ketogenic diets confirms that
"the mechanism underlying the increase of body fat utilization [on ketogenic diets] has some pathways in common with mechanisms contributing to the lack of muscle mass increase [which is why] during the ketogenic diet it is actually very difficult to increase muscle mass" (Paoli. 2012).
In their latest study, researchers from the University of Tampa tried to get to the bottom of this myth by looking at the degree of muscle protein synthesis (MPS) in rodents on carbohydrate-rich Western and low-carbohydrate "ketogenic" diets (see Figure 1 for the exact macronutrient ratios).
|Figure 1: Macro composition of the non-isocaloric chow (KD - 5.2 kcal/g, W - 4.5kcal/g | Mobley. 2015).|
|Figure 2: While the absolute figures have not yet been published, I can already tell you that - statistically speaking - the type of diet did not make a difference (Mobley. 2015)|
|While some people make it appear as if we already knew that ketogenic diets are superior, you may remember that some recent studies show that balanced diets have more favorable effects on the body composition of certain athletes | learn more|
- Even if it wasn't for the questionable control diet, there would still be one thing the data from Mobley's study cannot tell us and that's whether the putative reduction in IGF-1 that has been observed on low carbohydrate diets (Caton. 2012) may have long(er)-term detrimental effects on muscle gains. There is, as you as a SuppVersity reader will know, good evidence that IGF-1, despite its irrelevance for short term increases in muscle protein synthesis, may play an important role in the long-term adaptational response to exercise (I suggest you go back to this SuppVersity Classic Article if that's news to you). It's thus not just the fact that we are dealing with a rodent study here that makes me want to say that future long(er) term studies in humans are necessary before the myth that ketogenic diets may impair (long-term) gains can be put to rest once and for all.
- Is weight gain hardly possible on the ketogenic diet? Actually this is another common ketogenic diet myth: When you are consuming a ketogenic diet you cannot get fat. Sounds stupid, right? Well, if you look at a recent study that comes - just as the previously cited study - from the University of Tampa (Holland. 2015), would certainly appear as if there may be something to this claim.
In their 6-week rodent study, Angelina M. Holland and colleagues compared the effects of ketogenic (KD), Western (WD), and standard chow (StdChow) control diets on fat deposition and serum health-related biomarkers (exact macronutrient ratios are given in Figure 3).
Figure 3: Macronutrient composition of the diets in Holland's study (Holland. 2015).
As it was to be expected, the rats on the ketogenic diet consumed slightly less energy (3,540 ± 74 kcal) than those on the western diet (3,638 ± 83 kcal) over the course of the six week study. It is thus not surprising that there was a significant inter-group difference in terms in terms of the total amount of weight rodents in the KD and WD group gained: 397g vs. 494g to be precise.
Figure 4: Due to a significantly reduced feed efficacy (weight gain per energy intake) the rats on the ketogenic diet gained sign. less weight than both, the rats on the Western diet and standard chow (Holland. 2015).
That's a quite a remarkable result, but if the lack of weight gain applied only to the total amount of body weight, it would be difficult to decide whether that's a good or a bad thing. When the scientists took a look at the weight of the fat depots, however, it became clear that the lion's share of the weight difference was mediated by a lack of fat, not just weight gain.
"KD and StdChow had significantly less absolute and relative omental (absolute omental: 0.8 ± 0.3g and 1.2 ± 0.4g vs 1.6 ± 0.6g, respectively, p < 0.05; relative omental: 2.1 ± 0.7 and 2.4 ± 0.7 vs 3.2 ± 1.2g/kg, respectively, p < 0.05) compared to WD rats. KD and StdChow also had significantly less perirenal adipose tissue compared to WD (absolute perirenal: 4.2 ± 1.3 and 5.4 ± 1.4 vs 7.8 ± 1.8g, respectively, p < 0.05; relative perirenal: 10.6 ± 2.8 and 11.4 ± 2.4 vs 15.6 ± 3.0g/kg, respectively, p < 0.05). KD had significantly less absolute inguinal subcutaneous (SQ) and scapular brown fat than WD (absolute SQ: 4.3 ± 1.5 vs 6.6 ± 2.4g/kg; absolute brown fat: 0.6 ± 0.2 vs 0.8 ± 0.3g) but similar relative SQ and brown fat weights" (Holland. 2015).In view of the concomitantly reduced serum triglyceride levels (WD - 319.7 ± 109.8mg/dL versus StdChow 163.0 ± 67.0mg/dL and KD 69.9 ± 21.2mg/dL; p < 0.05), serum cholesterol and glucose levels glucose, the claim that ketogenic diets may help mammals to maintain stable body weights while improving, not messing with their glucose and lipid metabolism does therefore appear to be clearly supported by the study at hand. All that still has to be done before we can remove the "?" from the subheading that precedes the previous paragraphs would be a human study with a similar / identical design to exclude that any differences in glucose and, more importantly, fat metabolism in human beings increase the feed efficacy of the ketogenic diet to an extent that nullifies the benefits.
- Caton, Samantha J., et al. "Low-carbohydrate high-fat diets in combination with daily exercise in rats: effects on body weight regulation, body composition and exercise capacity." Physiology & behavior 106.2 (2012): 185-192.
- Cholewa, Jason M., et al. "The effects of a sports nutrition education intervention on nutritional status, sport nutrition knowledge, body composition, and performance in NCAA Division I baseball players." Journal of the International Society of Sports Nutrition 12.Suppl 1 (2015): P44.
- Holland, Angelia M., et al. "Ketogenic versus Western and standard chow diets favorably alters fat deposition and serum biomarkers in rats." Journal of the International Society of Sports Nutrition 12.Suppl 1 (2015): P21.
- Jones, Brian A., and Robert T. Davidson. "Muscle proportionality: The proportionality of skeletal muscle before and after intervention." Journal of the International Society of Sports Nutrition 12.Suppl 1 (2015): P51.
- Mobley, C. Brooks, et al. "The anabolic skeletal muscle response to acute resistance exercise is not impaired in rats fed a ketogenic diet." Journal of the International Society of Sports Nutrition 12.Suppl 1 (2015): P22.
- 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.
- Solomon, Todd M., et al. "A randomized, double-blind, placebo controlled, parallel group, efficacy study of alpha BRAIN® administered orally." Journal of the International Society of Sports Nutrition 12.Suppl 1 (2015): P54.