Energy Restriction + Whey = Dieting Success, BUT the Magic is not in the Alpha-Lactalbumin

Ever since the first studies showed the beneficial effect of dairy in general and whey in particular on weight loss induced by caloric restriction, scientists have been arguing for alpha-lactalbumin being the key, or at least one of the key factors that contribute to the anti-obesity effects of milk products.

A group of scientists from Finland (Shi. 2011) did now investigate the exact contribution of alpha-lactalbumin to the dairy / whey induced anti-obesity effects. For 50 days Shi et al. fed mice on one out of three isocaloric, energy restricted diets containing either casein (calcium 0.8%) or two different high-calcium (1.8%) whey protein-based (α-lac + Ca and AA + Ca) amino acid mixes, which differed only in the amount of a-lactalbumin they contained. The results contradict the hypothesis that alpha-lactalbumin is the/a major driving force behind dairy induced weight loss outcomes:

The mice on α-lac and AA lost significantly more weight and body fat than mice on casein diet (P < 0.05). There was no difference between α-lac and AA diets. Ad libitum feeding after weight loss resulted in weight regain and fat accumulation in all groups

So, in the end, it obviously all comes down to the amino acid composition of whey protein that makes it superior to casein, but not to a similarly composed amino acid mixture without the addition of the alpha-lactalbumin fraction. The fact that none of the tested proteins had an advantage over the other in a non-dieting (i.e. calorically not restricted) environment, also indicates that it is the improved provision of essential amino acids from whey, which makes the difference.

Figure 1: Body fat percentage of mice after 50 days on different calorically restricted dietary regimens (Shi. 2011)

Yet, other than the ever-growing leucine fan-group on the web may now be led to believe, a further in-group differentiation  (cf. figure 1) into mice receiving additional amino acids (+100% aspartic acid & tryptophan, or +100% leucine) shows that additional leucine does not improve, but in fact blunt fat loss. In this otherwise isocaloric environment, this is probably due to the reduced percentage of other (essential and conditionally essential) amino acids in the chow, the consequences of which may be impaired fatty acid oxidation and suboptimal metabolic function in general.

One last thing, though: Before you completely discard the value of casein or even alpha-lactalbumin in your diet, I better told you that, compared to the amino acid group (without alpha-lactalbumin), all four, the whey + alpha-lactalbumin (all three groups), as well as the casein group retained a higher amount of muscle mass than the amino acid group (cf. figure 2) - with the results for the +100% asp + trp and the +100% leucine being statistically significant.

Bottom line: To cut body fat use pure whey with natural alpha-lactalbumine to optimize fat loss and retain muscle mass. Since, the difference in muscle retention to the other whey + alpha lactalbumine groups is not significant, the addition of supplemental amino acids including the "holy" (you may recognize I cannot stand the way it is currently hyped by the industry) leucine could make sense if you want to gain muscle; according to the data from this study, it is yet superfluous if your intention is to cut body fat.

More Conflicting Evidence on Leucine Metabolite: HMB Makes Volleyballers Stronger.

The leucine metabolite HMB, i.e. β-Hydroxy-β-Methylbutyric acid, is unquestionable the comeback kid of the supplement industry. "It works!", "It's useless!", ... every now and then a new study supports one side of the debate. A group of international scientists does now present a study, which would support the use of the expensive, yet readily available amino acid.

Portal et al. (Portal. 2011) investigated the effect of 3g HMB/day "on body composition, muscle strength, anaerobic and aerobic capacity, anabolic/catabolic hormones and inflammatory mediators in elite, national team level adolescent volleyball players (13.5–18 years, 14 males, 14 females, Tanner stage 4–5) during the first 7 weeks of the training season". The results were unequivocal, yet not overtly impressive:

HMB led to a significant greater increase in FFM by skinfold thickness (56.4 ± 10.2 to 56.3 ± 8.6 vs. 59.3 ±  11.3 to 61.6 ± 11.3 kg in the control and HMB group, respectively, p < 0.001). HMB led to a significant greater increase in both dominant and non-dominant knee flexion isokinetic force/FFM, measured at fast (180°/sec) and slow (60°/sec) angle speeds, but had no significant effect on knee extension and elbow flexion and extension. HMB led to a significant greater increase in peak and mean anaerobic power determined by the Wingate anaerobic test (peak power: 15.5 ± 1.6 to 16.2 ± 1.2 vs. 15.4 ± 1.6 to 17.2 ± 1.2 watts/FFM, mean power: 10.6 ± 0.9 to 10.8 ± 1.1 vs. 10.7 ± 0.8 to 11.8 ± 1.0 watts/FFM in control and HMB group, respectively, p < 0.01), with no effect on fatigue index.

With no measurable effect on aerobic fitness, anabolic hormone levels or inflammatory mediators, the use of HMB appears to be advisable only in power and strength athletes.

If you are a bodybuilder on a high protein diet, I would however doubt that you would see any benefits from additional HMB. A diet rich in quality protein (high BCAA and particularly leucine content) should provide you with adequate amounts of leucine to keep endogenous HMB levels elevated.

Lower Protein to Carb Ratio Impairs Akt/TOR Signaling Pathway after Fasting in Rainbow Trout

"Boy, you need your carbs post workout!" This cornerstone of conventional bodybuilding wisdom is crumbling and a new study, if it had been done in humans, not in rainbow trout, would potentially refute this myth once and for all - at least, if one follows the popular (but false) assumption that it is because you are in a carb depleted or overall fasted state after a strenuous workouts.

A group of European scientists (Seiliez. 2011) investigated the effect of diets with different protein to carbohydrate ratios on the Akt/TOR Signaling Pathway after fasting for 48h. What they found contradicts conventional wisdom:

Activation of the Akt/TOR signaling pathway by refeeding was severely impaired by decreasing the proteins/carbohydrates ratio. Similarly, post-prandial regulation of several genes related to glucose (Glut4, glucose-6-phosphatase isoform 1), lipid (fatty acid synthase, ATP-citrate lyase, sterol responsive element binding protein, carnitine palmitoyltransferase 1 and 3-hydroxyacyl-CoA dehydrogenase) and amino acid metabolism (serine dehydratase and branched chain α-keto acid dehydrogenase E2 subunit) only occurred when fish were fed the high protein diet. On the other hand, diet composition had a low impact on the expression of genes related to muscle protein degradation.

So, not only did an increase in carbohydrates negatively impact muscle protein synthesis stimulated by the Akt/TOR signaling pathway, interestingly it also failed to reduce muscle protein degradation, which is the second reason people use in favor of a high carb meal after workouts (/fasting). 

For people following the research and writings of low carb proponents such as Mauro di Pasquale these results may not be surprising. However, before flushing your weight gainer down the toilette, you should really reevaluate your personal and training goals. For an athlete whose exercise bouts are long and frequent, carbohydrate repletion may well turn out to be beneficial. If not for muscle growth, then for performance maintenance. A general demonization of carbs would thus be similarly inappropriate as the "fat scare" of the late 20th century. It all depends on who you are and what your athletic and aesthetic goals are.

Both, Protein and Carbohydrate After Workout Ineffective in Ameliorating CK-Response and Muscle Soreness After Exercise

While people keep debating, whether you need or you do not need carbs post workout, a very recent US-study (Dahlstrom Burnley. 2010) shows that neither protein nor carbs effectively protect against CK-elevation and muscle soreness following an excentric strength training session.

Figure 1: Serum creatine phosphokinase (CPK) activity according to treatment.
*There was no significant difference in CPK activity (ANOVA) among treatment groups.

There are however two major drawbacks to this study. Firstly, the scientists do not quantify the amount of protein or carbohydrate the subjects consumed after their strength training session. And secondly, both CK elevations, as well as muscle soreness are part of the adaptation process, we actually train for. So, if protein & carbs do not reduce these overs signs of an ongoing adaptive response, this does not have to be a bad thing.

After all, this is thus another one of those studies especially protein-phobic Drs will cite in order to convince you that your protein drink, of which they will tell you that it will kill you, does not even help with muscle gains ;-)