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Minggu, 17 Januari 2016

Peri-Workout BCAA + Glutamine + Citrulline Consumption Blunts Muscle & Fat Loss Compared to Powerade Placebo

"Shed the fat, keep the muscle!" That's a promise you will find not literally, but analogously in every ad for BCAAs, but do they actually do that? Help you shed fat and retain muscle? Scientific prove to support this claim is, as of yet, missing.
With BCAAs it is just as it is with 99.9% of the supplements: Ads and product labels are full of scientifically unproven claims. One of these unproven claims is that the consumption of branched-chain amino acids would protect you from losing muscle while you're dieting ... the problem with this notion is - as sound as it may seem in view of the mTOR promoting effects of leucine, there's no study which would prove that guzzling BCAAs all day will in promote fat and blunt lean mass losses when you're cutting.... or I should say "as of now, there was no study...", right? After all, there's this new study by Dudgeon et al.'s the abstract of which tells us that "BCAA supplementation in trained individuals performing resistance training while on a hypocaloric diet can maintain lean mass and preserve skeletal muscle performance while losing fat mass" (Dudgeon. 2015).
Learn more about amino acid and BCAA supplements at the SuppVersity

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As we are going to see after taking a look at the design and results of Dudgeon's single-blind study in seventeen resistance-trained males (21–28 years of age) on hypocaloric diets, this is yet a potentially misleading conclusion. Not because it was wrong, but rather because it omits an observation that could be of paramount importance to dieters who have the free choice between the two treatments, the subjects of the study were randomly assigned to, namely...
  • 14g of Xtend (BCAA) before after workouts or
  • 14 g Powerade (CHO) before and after workouts
The supplements were consumed for a total study time of 8 weeks during which all subjects trained four times per week according to a standardized workout program and consumed a diet that was programmed (but not controlled) to contain roughly 35% less energy than the subjects required on workout days and approximately 10% less energy than required on off-days.
In the strict sense, this is actually no "BCAA study": Some of you may already have realized that the "BCAA supplement" the scientists used, i.e. Scivation XTend, is not really a "BCAA only" supplement. Next to only 7 grams of BCAAs per 14g of powder the subjects ingested before and after the workout, it also contains 1 g citrulline and 2.5 g glutamine and obviously a hell lot of flavorings, fillers and what not. Now, while the latter are not of any importance, both of the former have been heralded as muscle protectors, as well, with citrulline probably having the more convincing scientific data to back it up (it appears to act similar to leucine, by the way | Moinard. 2007; Faure. 2012; Ventura. 2013) outside of scenarios with extremely high glucocorticoid levels where glutamine unquestionably helps (Hickson. 1995 & 1997; Salehian. 2006). It is thus in my humble opinion at least highly imprecise to conclude that the provision of 2x7g of BCAA ameliorated the the fat to muscle loss ratio during the 8-week study.
Now you may be rightly asking yourselves why I am so vague with respect to the energy deficit. Well, everything we learn from the full text of the study is that all subjects were "provided an individualized caloric restricted diet based on individual data (body mass, body composition, resting metabolic rate, etc.)" (Dudgeon. 2015) - a diet the scientists describe as follows:
Table 1: W/ the Harris-Benedict equation you calculate the basal metabolic rate and multiply it with a factor (multiplier) that describes your activity level best to arrive at the "real" estimated energy requirements.
"The caloric-restricted diet was designed as an 8 week “cut diet” for reducing body fat, and used a modified carbohydrate-restricted diet approach (percent of total calories for workout days were 30 % carbohydrates, 35 % protein and 35 % fat and for off days were 25 % carbohydrates, 40 % protein and 35 % fat). Each individual’s daily caloric and macronutrient intake was determined using the Harris Benedict formula with an activity factor of 1.35 (lightly active individual engaging in light exercise 1–3 days/week) for workout days and 1.125 (sedentary individual) for off days" (Dudgeon. 2015).
Since the Harris-Benedict formula is only a really rough estimate of how much energy you actually need, my previous estimations of the energy deficit are as "accurate" as I can possibly be. The 1604kcal that are printed in red bold letters on top of the exemplary meal plan in Figure 2, however, suggest that the deficit on the off days was significantly larger. After all, the subjects' mean weight was >80kg and their daily energy requirements should thus be at least 2,000kcal - even on off days (and the table in which the macronutrient composition is listed actually says that the mean intake was 2046 and 2264kcal/day for the BCAA and CHO group respectively).
Table 2: Sample dietary card for a subject during an off, non-workout, day (Dudgeon. 2015).
In view of the fact that the response I got from the authors to an email in which I asked about the exact kcal deficit only referred me to the previously cited passage about the activity factors, I guess it is futile to further speculate about the energy deficit, of which I would still like to add that it was probably higher in the heavier and taller BCAA group. Why? Well, the BCAA group had plans with 2456 and 2046 kcal on workout and off days, the CHO group on the other hand were fed 2717 and 2264 kcal... Whatever, let's get to the more relevant, but not less confusing changes in body weight, lean mass and fat mass the researchers report for the BCAA and CHO groups:
Figure 1: Pre and post absolute mean body weight, body fat and lean body mass values before and after the 8-week intervention; * p < 0.05 for the difference within groups (no difference between groups | Dudgeon. 2015)
-0.1 kg and -2.3 kg of body weight, +0.4 kg and -0.9 kg of lean mass and 0.6 kg and 1.4 kg fat mass in the BCAA and CHO groups respectively - that's in line with the previously cited conclusion. The BCAA supplement blunted the small loss of lean mass in the CHO group, but if we look at the complete dataset, a somewhat different image emerges; one in which the two classic markers of body composition, namely the relative amount of body fat (aka "body fat percentage") and the lean mass as percentage of the total mass changed in a way that favors CHO over BCAA supplements:
Figure 2: Pre vs. post values for body fat % and lean mass %, the two parameters you would classically use to assess body composition (instead of absolute lean and fat mass); pre-to-post change on top of the post-bars (Dudgeon. 2015).
Now, I am not saying that the consumption of the BCAA (+citrulline + glutamine) supplement did not blunt the loss of lean mass - it obviously did. What I want you to keep in mind, though, is the fact that the consumption of 14g of BCAAs before and after workouts appears to suffocated any dieting efforts - after all, the subjects lost a practically irrelevant (and for whatever reason allegedly statistical significant) amount of 600g body fat; that's in contrast to the 1.4 kg of fat mass the subjects in the control group lost; and that's a practically relevant insight, even if this fat loss was allegedly statistically non-significant, because  it implies that BCAAs practically blunt fat loss.
Whey + Casein - A Superior Post-Workout Shake that Kicks Every Amino Acid Product's Ass | read more
So what do we make of this study? Well, first of all, I would like to come back to something fundamental: This is yet another BCCA study that did not make the practically most relevant comparison of BCAAs and cheap (whey) protein protein supplements, in which BCAAs have hitherto always failed. In my humble opinion that's a problem, after all having a carbohydrate supplement as control in a dieting study is nice, but eventually not relevant for the average trainee who is probably not really considering extra-carbs when he's dieting.  What a real trainee would have been interested in, is whether BCAAs can prevent muscle catabolism to a significantly greater degree than the cheap whey protein he's using anyway...

... and maybe, whether the latter has a similar negative effect on fat loss as the BCAAs in the study at hand - which leads me to the actual take home message of the study, which is, as usually, not as straight forward as the conclusion of the abstract suggested. When all is said and done, the study at hand does after all suggest that someone who is approaching the single-digit body-fat zone, where every gram of muscle that is not lost counts, could benefit from the apparent lean mass protective effects of BCAA the scientists observed in the study at hand. It does yet also indicate that someone who's "making weight" for a competition should take a second look at the data in Figure 1 + 2 and acknowledge that taking a BCAA supplement may be the reason he will fail to achieve his weight loss goal. You don't believe that? Well, let's do some scientifically not exactly kosher extrapolations: If you manage to lose 10 kg in 10 weeks without BCAAs, for example, the data from the study at hand suggests that your weight loss "on BCAAs" over the course of those 10 weeks would be as meager as 434 grams ... whether that's in fact the case (I doubt it ;-) will have to be studied in future studies, just like the effect of BCAAs, citrulline and glutamine, alone and whether using your regular whey protein before and after the workout wouldn't have the exact same, or even better effects | Comment on Facebook!
References:
  • Dudgeon, WD; Page Kelly, E; Scheett TP. "In a single-blind, matched group design: branched-chain amino acid supplementation and resistance training maintains lean body mass during a caloric restricted diet." Journal of the International Society of Sports Nutrition  (2016) 13:1.
  • Faure, Cécile, et al. "Leucine and citrulline modulate muscle function in malnourished aged rats." Amino acids 42.4 (2012): 1425-1433.
  • Moinard, Christophe, and Luc Cynober. "Citrulline: a new player in the control of nitrogen homeostasis." The Journal of nutrition 137.6 (2007): 1621S-1625S.
  • Hickson, R. C., S. M. Czerwinski, and L. E. Wegrzyn. "Glutamine prevents downregulation of myosin heavy chain synthesis and muscle atrophy from glucocorticoids." American Journal of Physiology-Endocrinology and Metabolism 268.4 (1995): E730-E734.
  • Hickson, Robert C., et al. "Protective effect of glutamine from glucocorticoid-induced muscle atrophy occurs without alterations in circulating insulin-like growth factor (IGF)-I and IGF-binding protein levels." Experimental Biology and Medicine 216.1 (1997): 65-71.
  • Salehian, Behrouz, et al. "The effect of glutamine on prevention of glucocorticoid-induced skeletal muscle atrophy is associated with myostatin suppression." Metabolism 55.9 (2006): 1239-1247.
  • Ventura, G., et al. "Effect of citrulline on muscle functions during moderate dietary restriction in healthy adult rats." Amino acids 45.5 (2013): 1123-1131.

Sabtu, 10 Oktober 2015

Post-Workout Coffee Boosts Glycogen Repletion by Up to 30% and May Even Have Sign. Glucose Partitioning Effects

Yes, I do suggest that it may be beneficial to drink these two and another two cups of coffee w/ lots of sugar after your workout - if you are an athlete, at least.
A delicious and refreshing pre-workout coffee or just plain caffeine from pre-workouts are probably on the supplement list of most of the SuppVersity readers. Whether the same is the case for a post-workout coffee, let alone caffeine tablets, though, is questionable. Just as questionable, as the common belief that you better stay away from coffee at any time after your workouts, by the way.

If you look at the existing literature, the effects of post-workout caffeine ingestion are not exactly an intensely researched area. And still, the evidence does more or less strongly support the notion that a post-workout coffee could be as beneficial as its pre-workout analog - in a different area.
You can learn more about coffee at the SuppVersity

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Caffeine Resis- tance - Does It Even Exist?
Initial evidence that the post-workout ingestion of caffeine may have beneficial effects on post-workout gylcogen resynthesis and thus an important part of the recovery process comes from a 2004 study by Battram et al. (2004). Back in the day, Battram assumed - just like you probably did - that the ingestion of caffeine after prolonged exercise would impede the resynthesis of proglycogen and macroglycogen carbohydrate supplementation in humans.
Figure 1: Total glycogen [proglycogen (PG) macroglycogen (MG)] glycogen concentrations during 5 h of recovery in the placebo trial (A) and caffeine trial (B | Battram. 2004).


As you can easily see if you compare the data in Figure 1 (A) for the placebo trial with the data in Figure 1 (B), which was generated in the trial in which the healthy young men who participated in Battram's study received a whopping dose of 6mg/kg of caffeine, there is no ill effect on post-workout gylcogen resynthesis even with high dose caffeine supplementation.
"In conclusion, Caf ingestion does not impede the resynthesis of PG or MG after an extensive depletion of muscle glycogen and with the provision of exogenous dietary carbohydrate" (Battram. 2004).
As surprising as this may be in view of the inhibitory effect of caffeine on full-body glucose uptake (in Battram's study there was also a significantly higher blood glucose concentration in the caffeine
trial), Battram's results are still no outliers. Rather than that, a follow up study by Pedderson et al. found that, in trained subjects, coingestion of large amounts of Caff (8 mg/kg BM) with CHO has an additive effect on rates of postexercise muscle glycogen accumulation compared with consumption of CHO alone" (Pedderson. 2008).
Even though Beelen's study does not support the the superior effect of caffeine on muscle gylcogen, it does at least show that the effect (if it occurs) would probably be identical for fast- and slow-twitch muscles and thus similarly beneficial for strength and endurance athletes (Beelen. 2011).
So, there is no doubt that this works? Well, as usual, there is doubt. Another 2011 study by Beelen et al. did not find the same increases in glycogen resynthesis. It is well possible, though that this was due to either the fact that they pumped their subjects up with even higher amounts of carbs, though (1mg/kg/h in Pedderson vs. 1.2mg/kg/h in Beelen) and lower amounts of caffeine (15% less). In view of the fact that the exercise protocol used in the study only halved the glyocogen levels of the subjects, while it was reduced by >75% in the Pedderson study, the lack of effect may also be a result of the lack of full glycogen depletion in Beelen's study (unfortunately, the authors don't provide their values only in arbitrary units - that's why I can't tell you with certainty to which degree this may have influenced the results).
In that, it is important to point out that the increased glycogen resynthesis in Pedderson's randomized, double-blind crossover study, in which the young well-trained subjects performed intermittent exhaustive cycling and then consumed a low-CHO meal before they rode until volitional fatigue and consumed either
  • CHO [4 g/kg body mass (BM)] alone or
  • CHO [4 g/kg body mass (BM)] with Caff (8 mg/kg BM)
at the beginning of the 4 h of passive recovery phase, did not occur at the expense of the restoration of the high energy substrates ATP and PCr (see Figure 2) - since the latter two are especially relevant for people who lift weight, sprint and do other high intensity stuff, there's no reason to believe that the caffeine + sugar post-load was something only endurance athletes could use.
Figure 2: High dose caffeine (8mg/kg) increases glycogen resynthesis after exhausting workouts without having ill effects on the resynthesis of ATP and PCr (Pedderson. 2008).
Apropos "using" this strategy: Another three years later, Taylor et al. (2011) expanded on the results of Battram (2004) and Pedderson (2008) in a study in which they went beyond testing the mere amount of glycogen that was transported into the muscle and evaluated its effect on the subjects' performance in a post-recovery high-intensity interval-running capacity test.
Figure 3: Exercise capacity during the Loughborough Intermittent Shuttle Test for the carbohydrate (CHO), CHO plus caffeine (CHO+CAFF), and water (WAT) trials. Lines represent individual subject responses (Taylor. 2011).
As you can easily see in Figure 3, the HIIT advantage, which was tested 4h after the glycogen-depleting exercise protocol and the ingestion of 1.2g/kg carbohydrate +/- 8mg/kg caffeine via an Intermittent Shuttle Test (LIST) to volitional exhaustion, was about as pronounced as the glycogen-advantage Pedderson et al. observed three years before (albeit with some inter-individual differences).
Why would you say caffeine may have a partitioning effect? The answer is easy: While fat cells need insulin to transform and store significant amounts of glucose, muscle cells don't - specifically after workouts the increase in GLUT-4 receptor expression and glucose uptake occurs largely without requiring insulin as a trigger. Now, caffeine's ill effects on blood glucose are due to its ability to block the insulin signalling via beta-adrenergic activity (Thong. 2002). It should thus reduce the glucose uptake by the fat cells while decreasing the rate, but not the total amount of glucose that is taken up and stored by the muscle... speaking of rate and total amount: This hypothesis is fully in line with the initially cited study by Battram et al. who observed just that: a decreased rate, but identical total increase in muscle glycogen.
So why haven't we been taking our post-workout caffeine for years, now? Well, I guess the reason is that it is not sure how the effects of caffeine on the sympathetic nervous may effect other factors of the recovery process. In view of the fact the central nervous system will be "on fire" after any workout, though, it is questionable whether adding in 400-800mg caffeine will actually affect its recovery.

A better reason for not (yet) subscribing to the post-workout caffeine binges would thus be that (a) few of us actually need to refill their glycogen stores in 4-6h after a workout and that we (b) have no real clue what the mechanism is. If it was actually - as some of the data would suggest - a selective inhibition of fat cell glucose uptake (see box on the right), even those of us who don't have to restore their glycogen stores as fast as possible may see beneficial effects on body composition. If, on the other hand, it works by stimulating the intestinal absorption of glucose, only (cf. Van Nieuwenhoven. 2000), the real world implications for the average trainee would be significantly less pronounced | Comment on Facebook!
References:
  • Battram, Danielle S., et al. "Caffeine ingestion does not impede the resynthesis of proglycogen and macroglycogen after prolonged exercise and carbohydrate supplementation in humans." Journal of Applied Physiology 96.3 (2004): 943-950.
  • Beelen, Milou, et al. "Impact of caffeine and protein on postexercise muscle glycogen synthesis." Med Sci Sports Exerc 44.4 (2012): 692-700.
  • Pedersen, David J., et al. "High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine." Journal of Applied Physiology 105.1 (2008): 7-13.
  • Taylor, Conor, et al. "The effect of adding caffeine to postexercise carbohydrate feeding on subsequent high-intensity interval-running capacity compared with carbohydrate alone." International Journal of Sport Nutrition andExercise Metabolism 21.5 (2011): 410.
  • Thong, Farah SL, and Terry E. Graham. "Caffeine-induced impairment of glucose tolerance is abolished by β-adrenergic receptor blockade in humans." Journal of applied physiology 92.6 (2002): 2347-2352.
  • Van Nieuwenhoven, M. A., R-JM Brummer, and F. Brouns. "Gastrointestinal function during exercise: comparison of water, sports drink, and sports drink with caffeine." Journal of applied physiology 89.3 (2000): 1079-1085.