Intermittent Fasting Diet Plan Example

We are what we eat! Acknowledged, but does this also go for your hormones and different in protein intakes? Lets have another look at the contemporarily available research to figure that out.

In recent study in the International Journal of Sport Nutrition and Exercise Metabolism a group of researchers from the Faculty of Physical Education and Recreation at the University of Alberta reports: "Supplementing a typical daily food intake consisting of 0.8 g of protein·kg-1·d-1 with a whey protein isolate (an additional 0.8 or 1.6 g·kg-1·d-1) [...] had no effect on glucose, insulin, testosterone, cortisol, or growth hormone following the final meal" (Forbes. 2013).

I know, anything else would have been a real shocker. What it wouldnt be, though, is a total surprise. If you dig through the available literature you can easily find data that would support the scientists assumption that doing an experiment "to investigate the effects of a controlled typical one day diet supplemented with two different doses of whey protein isolate on blood amino acid profiles and hormonal concentrations following the final meal" (Forbes. 2013) would be a good idea.

True or false? Certainly TRUE!

No, I am not kidding you! We do have plenty of evidence of direct interactions between chronic high vs. low protein intake and the production and metabolism of hormones, like testosterone, cortisol, their corresponding binding proteins, SHGB and CBP, and a whole host of other molecules that act like hormones, although we often dont call them "hormones". Examples? Well, here you go:

• Low protein = low SHBG (Longcope. 2000) - At least in the 1552 men in their "best age" (40-70 years) who participated in a study by scientsts from the University of Massachusetts Medical School the consumption of a diet that had less than the average 80g/day of protein in it lead to decreases in SHBG and corresponding increases in free (~bioavailable) testosterone. Age, dietary fiber, and smoking, on the other hand were positively correlated with SHBG.
• Chronically high protein intakes (40% of total energy) lower testosterone / cortisol ratio (Oi. 2001) - The highly significant increase in cortisol and corresponding decrease in the testosterone to cortisol ratio, Oi et al. report in a 2001 paper have luckily (a) been observed in rodents, only, and thats actually the main finding of the study (b) could be countered by the administration of garlic extract.
  
  

  Figure 1: In rodents, a high protein intake (40% of total energy from casein) will increase cortisol at stable T-levels and thus decrease the testosterone : cortisol ratio (Oi. 2001)

  I can only speculate whether and to which degree the endocrine effects of high protein diets differ between rats and men (the Anderson study discussed below suggests they dont) - and you know I love facts and hate speculations and unsupported hypothesis. So I stick to an assumption I could support, i.e. the supposition that the improvements in testosterone, the researchers observed, when they fed their rodents garlic was mediated  by its glutathione (GSH) boosting effects. These effects - and you as a regular SuppVersity reader know that are not "garlic exclusive". Whey protein, for example will also increase GSH (Bounous. 1989). Obviously whey doesnt increase your testosterone, but a "protein overload" from a glutathione boosting protein source may not have to be countered by GSH boosters in the first place.
• A high protein : carb ratio decreases total testosterone levels in man (Anderson. 1987) - Some people live by the principle that things that mustnt be. As a SuppVersity reader you obviously dont belong to this group of people and will thus be willing to accept that Anderson et al. were able to show that...

  "[...] the testosterone concentrations in seven normal men were consistently higher after ten days on a high carbohydrate diet (468 ± 34 ng/dl, mean ± S.E.) than during a high protein diet (371 ± 23 ng/d1, p<0.05) and were accompanied by parallel changes in sex hormone binding globulin (32.5 ± 2.8 nmol/1 vs. 23.4 ± 1.6 nmol/1 respectively, p<0.01)." (Anderson. 1987)

  As a SuppVersity reader you are yet also smart enough to know that this data is irrelevant, without adequately measured free testosterone levels: If we do the math and calculate the latter (obviously not 100% accurately), i.e. free testosterone on normal protein diet: 9.4 ng/dL  =  2.01 % vs. free testosterone on high protein + low carb diet: 9.02 ng/dL  =  2.43 %, the difference does no longer look so bad, anyway - does it?
  
  

  Figure 2: Total (TT in ng/dL) and free testosterone (FT in ng/dL), SHBG (µg/L) and testosterone : cotisol ratio after one months on high protein + low carb vs. control (Anderson. 1987)

  This would not change the fact that youd suffered a -42% decrease of the testosterone : cortisol ratio from 60.5 to 35 which occurred in the Anderson study, when the participants were put on a meat, fish, poultry, egg white, and protein supplement based 44% protein, 35% carbohydrates, 21% fat diet.
• A high protein very low calorie diet can increase testosterone levels, but it will do so only if it is used to produce significant weight loss in obese adolescents, whose abundant body fat stores are gnawing away their androgens. In a corresponding study by Brown et al., the eight 11-15-year-old boys and girls where put on liquid (starvation) diets with a protein / carb / fat ratio of 67% / 28% / 5% that containing a total of 492-709 kcal per day.

  Figure 3: Total testosterone levels (ng/dl; left axis) and insulin levels (in µU/ml) in 14 (subj. 3 & 7) and 18 year-old male adolescents before and after 5 weeks on low calorie high protein liquid diets (Brown. 1983)

  As you can see in Figure 3 the significant reduction in body weight (13.5 kg total, 70-75% fat) went hand in hand with improvements in insulin sensitivity and the previously mentioned increase in total testosterone levels in the 14 year-old subjects 3 & 7 and the 18 year-old male adolescents (subject 6) - the only subjects for whom a complete testosterone panel was available.
• High protein diets are driving forces of GH induced skeletal muscle IGF-1 expression (Sanchez-Gomez. 1999) - With IGF-1 being equally important to men and women, it does not matter that the "subjects" in the study at hand were female growing rats that received either a high- or a low-protein diet with crude protein contents of 222 and 83 g/kg respectively.
  
  After 14 days on which the rodents were concamittantly injected with saline control, or growth hormone (rhGH) or recombinant human IGF-I (rhIGF-I) at dosages of 350 and 500µg/day, respectively, Sanchez-Gomes et al. observed that
  

  • Learn more about IGF-1.

    ...the low-protein diet alone reduced IGF-I concentrations in serum and in tissue taken from the gastrocnemius muscle as well as IGF-I mRNA from the same muscle, significantly.
  • ...the high protein diet amplified the retention of injected rhIGF-I in the muscle tissues and was associated with significant improvements of the nitrogen balance
  Based on these results, Myriam Sanchez-Gomez conclude that "the level of dietary protein ingested regulates not only the effect of IGF-I on whole-body N economy but also the regulation of IGF-I gene expression in muscles" (Myriam Sanchez-Gomez. 1999). 
• Increased f 2-hydroxylation of endogenous estrogen with high protein diets could have cancer protective effects (Anderson. 1984) - Certainly far fetched but not impossible is the connection between the increased 2-hydroxylation of endogenous estrogen in response to high protein diets Anderson et al. observed in a 1984 study in male study participants and the significant association between lower ratios an the risk of breast cancer (Liehr. 1996).
  
  

  Table 1: Cox regression of energy-adjusted dietary predictors of breast cancer recurrence and death (Saxe. 1999)

  It goes without saying that this is nothing but a hypothesis - a hypothesis that would yet be supported by a 1999 paper on "dietary predictors of breast cancer recurrence and death" by Saxe et al. which is based on one of the few papers that did not control for "meat" intake (you know that Pizza Salami qualifies as "meat", right?) in which each 5% increase in protein intake was associated with risk reductions of 18% for breast cancer recurrence and 44% for death in premenopausal women (Saxe 1999).
  
  And whats more, the fact that the associations were less pronounced in the post-menopausal study participants (the "low estrogen counterpart", if you will; see Table 1) only support the notion that the protective effects of protein may (at least in part) be mediated by its effects on estrogen metabolism.

References:

• Anderson, K. E., Kappas, A., Conney, A. H., Bradlow, H. L., & Fishman, J. (1984). The influence of dietary protein and carbohydrate on the principal oxidative biotransformations of estradiol in normal subjects. Journal of Clinical Endocrinology & Metabolism, 59(1), 103-107.
• Anderson, K. E., Rosner, W., Khan, M. S., New, M. I., Pang, S., Wissel, P. S., & Kappas, A. (1987). Diet-hormone interactions: protein/carbohydrate ratio alters reciprocally the plasma levels of testosterone and cortisol and their respective binding globulins in man. Life Sciences, 40(18), 1761-1768.
• Bounous, G., Gervais, F., Amer, V., Batist, G., & Gold, P. (1989). The influence of dietary whey protein on tissue glutathione and the diseases of aging. Clin Invest Med, 12(6), 343-9. 
• Brown, M. R., Klish, W. J., Hollander, J., Campbell, M. A., & Forbes, G. B. (1983). A high protein, low calorie liquid diet in the treatment of very obese adolescents: long-term effect on lean body mass. The American Journal of Clinical Nutrition, 38(1), 20-31. 
• Forbes, S. C., McCargar, L., Jelen, P., & Bell, G. J. (2013). Dose Response of Whey Protein Isolate in Addition to a Typical Mixed Meal on Blood Amino Acids and Hormonal Concentrations. International journal of sport nutrition and exercise metabolism. 
• Liehr, J. G., & Ricci, M. J. (1996). 4-Hydroxylation of estrogens as marker of human mammary tumors. Proceedings of the National Academy of Sciences, 93(8), 3294-3296.
• Longcope, C., Feldman, H. A., McKinlay, J. B., & Araujo, A. B. (2000). Diet and sex hormone-binding globulin. Journal of Clinical Endocrinology & Metabolism, 85(1), 293-296. 
• Sanchez-Gomez, M., Malmlöf, K., Mejia, W., Bermudez, A., Ochoa, M. T., Carrasco-Rodriguez, S., & Skottner, A. (1999). Insulin-like growth factor-I, but not growth hormone, is dependent on a high protein intake to increase nitrogen balance in the rat. British Journal of Nutrition, 81(02), 145-152.
• Saxe, G. A., Rock, C. L., Wicha, M. S., & Schottenfeld, D. (1999). Diet and risk for breast cancer recurrence and survival. Breast cancer research and treatment, 53(3), 241-253.

Alanine is the livers favorite gluconeogenic amino acid and leucine appears to increase its usage.

Being among the first to learn about the "Glucose-Repartitioning Effect of Iso-Leucine" in February 2013 (read up on it), you, as SuppVersity reader, belong to the selected few who know that valine and isoleucine may be more than unnecessary props in the leucine-powered BCAA show. With the recent publication of a rodent study from the University of Sao Paulo in Brazil (Campos-Ferraz. 2013), however, it looks as if you had to revise your perspective on the purportedly auxiliary BCAAs - at least, with respect to their ability to reduce fatigue, and muscle and liver-glycogen degradation, in trained rats and possibly (!) humans.

So what did the Brazilian researchers do?

Basically, the idea Campos-Ferraz et al. had in mind, when they came up with their 8 week exercise + 2 week supplementation protocol (see Table 1) was to ...

Table 1: Exercise progression; suppl. was initiated in w7 after lactate test

"evaluate effects of the use of supplementation with leucine or a mixture of BCAAs in trained rats submitted to an exercise-induced protocol of glycogen depletion.

Furthermore, we attempted to investigate muscle and liver biochemical parameters that were not performed in the previous study in order to elucidate the role of BCAAs in glycogen depletion. " (Campos-Ferraz. 2013)

In other words: The researchers wanted to find out whether or not leucine would exert identical, less or more pronounced effects on muscle glycogen use and endurance performance in rodents that the full spectrum of branch-chained amino acids, i.e. leucine, valine and isoleucine.

Contrary to what bro-science and the shiny ads of the supplement industry are suggesting, the scientists fundamental hypothesis was that the BCAAs supplementation would impair the rodents endurance capacity, because the branched-chain amino acids would be used in muscle to yield acetyl-CoA. This, in turn could reduce the activity of the glucose-alanine cycle, by which the muscles are supplied with alanine-derived glucose from the liver and (once the BCAAs got burne) result in an earlier onset of fatigue.

BCAAs are "glycogen depleters"?!

If you take a look at the data Campos Ferraz et al. gathered in the testing sessions at the end of the supplementation period, in the course of which the rats received an oral gavage of 166mg/kg per day (in human terms this would be ca. 3-3.5g per day) of BCAAs or leucine, it is quite obvious that the  the leucine group had a significantly lower muscle and liver glycogen degradation ratios than the BCAA group.

Figure 1: Liver & mucle glycogen degradation and time to exhaustion (expressed relative to placebo); muscle TCA intermediate content and enzyme activity / concentration (Campos-Ferraz. 2013)

Compared to the placebo group, only the ratios were different.  While the placebo group had the lowest liver glycogen use and a high muscle glycogen use, the supplemental leucine induced a shifted from muscle to liver glycogen and did thus exert muscle specific glycogen sparing effects.

As the researchers point out, these observations stand in line with their original hypothesis: Leucine can spare a significant amount of muscle and liver glycogen and thus produce a highly significant increase in resistance to exhaustion compared to the mixture of BCAAs (P<0.001).
If we compare the endurance performance of the leucine rodents to that of the placebo group, this does yet cast a slight shadow on the overall image of the glorious ergogenic, and, even more so, the purported performance enhancing effects of BCAAs. Despite measurable differences in the time to exhaustion, the actual endurance increase in response to the leucine supplement is relatively small.
 
If you take another look at the data in Figure 1 you will probably notice the significant increase in TCA cycle intermediates (citrate and malate) in the BCAA group. These changes provide further evidence that the provision of all three branch-chain amino acid emphasized the use of glucose as a main substrate to sustain the endurance activity.

"Mouse vs. man": Can we ignore the differences in BCAA metabolism?


At this point, it may however be about time to point out that the activity of the BCAA catabolizing enzyme branched-chain keto acids dehydrogenase complex (BCKD) in humans is quite different from that in rats.

"In the latter [the rat], liver BCKD is almost completely unphosphorylated (activated) in basal state, making it possible to metabolize more rapidly BCKA from the portal blood; in humans, BCKD in liver is normally phosphorylated (inactivated) in order to spare BCAAs for protein synthesis." (Campos-Ferraz. 2013)

In other words: While rodents use BCAAs mostly as an energy source, the human body spares them as a potential protein anabolic.

In view of the fact that the BCAAs are not used to the same degree as an alternative substrate in the human vs. the rodent liver, it is actually not very surprising that the results of the study at hand appear to conflict with data from a previous study by the same laboratory (Gualano. 2011). In the corresponding experiment, Gualano et al observed measurable increases in exercise capacity and lipid oxidation in human subjects during endurance exercise after muscle glycogen depletion in response to the provision of 300mg/kg BCAAs per day.

Reference:

• Campos-Ferraz PL, Bozza T, Nicastro H, Lancha AH Jr. Distinct effects of leucine or a mixture of the branched-chain amino acids (leucine, isoleucine, and valine) supplementation on resistance to fatigue, and muscle and liver-glycogen degradation, in trained rats. Nutrition. 2013 Nov-Dec;29(11-12):1388-94.
• Gualano AB, Bozza T, Lopes De Campos P, Roschel H, Dos Santos Costa A, Luiz Marquezi M, et al. Branched-chain amino acids supplementation enhances exercise capacity and lipid oxidation during endurance exercise after muscle glycogen depletion. J Sports Med Phys Fitness 2011;51:82–8