Endurance Athletes May Benefit From High-GI Meals Before Competition: 18% Increased Endurance During Time Trial

Endurance Athletes May Benefit From High-GI Meals Before Competition: 18% Increased Endurance During Time Trial

GI glucose glycemic index high GI low GI performance preworkout time to exhaustion TTE

Hillariously sweet, super cheap, and surprisingly effective: glucose!

While most of you will probably already have discarded the notion that you can only lose weight if you eat a diet with an extremely low GI (on a side note: Taubes' own study falsified his "insulin theory of obesity", recently), the notion that the ingestion of high glycemic index foods before exercise could ruin your performance, because your glucose levels, after an initial spike, will plummet and you will crash, still looms large.

With that being said, athletes around the world have, somewhat paradoxically, stuck to complex carbs before competition only to then fuel their performance with extremely sugary intraworkout bars, gels and drinks.

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Now, a recent study from the University of Florida, shows that "a fiber-free, glucose-derived meal may be superior to a low glycemic fiber-free whole meal in supporting moderately high intensity exercise in some highly motivated recreationally trained endurance athletes" (my emphasis in Waggener. 2016) - not exactly what you'd expect, right?

No reason to feel embarrassed, though: Even the authors of said study expected that their likewise fiber-free whole milk supplement with a low glycemic (LGM | GI = 41), would "equal or surpass the effects of an iso-kilocaloric, high glycemic (HGM) pre-exercise meal of glucose" (GI = 100).

Timing + intensity (and fiber) may matter, here! While there are surprisingly few studies that actually compare high vs. low GI carbohydrate sources pre-workout, a 2001 study by Kirwan using totally different CHO-sources (2 different breakfast cereals: rolled oats (moderate GI, 61; MOD-GI) or puffed rice (high GI, 82; HI-GI), combined with 300 mL of water) suggests that high-fiber low GI meals are advantageous if (a) the time-trial begins after 45 minutes of rest (instead of 2h of medium-intensity exercise) and you are (b) training / competing at a low intensity of only 60% VO2peak and thus for 2h+, which is obviously not exactly representative of endurance sports competitions or resistance training workouts w/ higher intensities.

Furthermore, the scientists expected that both would kick the ass of an artificially flavored placebo. when either of the three treatments was consumed 30 minutes before a 2-hr submaximal steady state ride at 55% of VO2 max that was followed by brief rest, and then by a final time-trial to exhaustion on the cycle ergometer (TTE) at 80% of VO2 max - the test was repeated on three separate days.

"The test drinks in this study consisted of whole cow’s milk (837.2 kJ / 320 ml fluid volume: 16 g carbohydrate, 10.7 g fat, and 10.7 g protein; Publix, Inc.) and two contrast drinks, one consisting of glucose polymer drink iso-kilocaloric to the whole milk supplement (837.2 kJ / 300 ml fluid volume: 50 g carbohydrate, 0 g fat, and 0 g protein; Cardinal Health, McGraw Park, IL) and a placebo/control drink (water). The placebo was an artificially flavored, unsweetened beverage (2 g of NutraSweet in 300 ml bottled water; [...])" (Waggener. 2016).

To avoid that the subjects' baseline diet would mess with the results, the diet in the days before the test was standardized (high in carbs 60.5% = typical end. athlete diet) and controlled via food logs.

Figure 1: Stamina (length in minutes) during the time trial after 1h of low-medium intensity exercise (Waggener. 2016).

Much in contrast to what the scientists expected, the LGM (whole milk) did not exert a greater ergogenic effect in this study when compared to the isokilocaloric HGM (glucose).

In fact, there was a non-significant (+18% time to exhaustion, blue bar in Figure 1 | not significant due to the large inter-individual differences) advantage for the HGM meal, which outperformed both, the LGM and the placebo on the most important test: the time to exhaustion trial - and that in spite of the fact that it was performed after a 2h! medium intensity workout, during which the subject's serum glucose and insulin levels should have performed the initially hinted at, purportedly ergolytic (=the opposite of performance-enhancing) roller-coaster ride.

Ah, and before you ask: The carbs - high or low GI - did not reduce the fat oxidation, the respiratory quotient was the same. Intra-workout fat oxidation doesn't matters much (or not at all) for fat loss, but alas... (Waggener. 2016).

Bottom line: As surprising as it may seem, the scientists' conclusion that a glucose-derived meal "may be superior to a low glycemic fiber-free whole meal in supporting moderately high intensity exercise in some highly motivated recreationally trained endurance athletes" (Waggener. 2016), is accurate, even if the time between the ingestion of the glucose solution and the actual high intensity work is so long that the "high GI carb bashing) would have you expect the athletes to fall into a hypoglycemic coma ;-)

What? Oh, yes! It would certainly be nice to see this being repeated with different types of exercises or athletes, but with the recreationally trained cyclists with a rather wide range of relative VO2 max values, the subjects in the study at hand are more representative of the average fitness enthusiast than pro-athletes or noobs | Comment on FB!

References:

• Kirwan, John P., et al. "Effects of moderate and high glycemic index meals on metabolism and exercise performance." Metabolism 50.7 (2001): 849-855.
• Waggener, Green T., et al. "The Effect of a Low Glycemic vs. High Glycemic Pre-Exercise Meal in Recreationally Trained Endurance Cyclists." (2016).

2-aminoisoheptane aka DMHA or Octadrine, a Legit DMAA Successor? Structure, Effects & Sides Suggest: "Maybe"

2-aminoisoheptane aka DMHA or Octadrine, a Legit DMAA Successor? Structure, Effects & Sides Suggest: "Maybe"

cognitive performance DMAA DMHA fat burner health lose fat performance preworkout PWO stimulant stimulants

DMHA is rather a stim than a fat burner. But I guess it will be marketed as both.

If you are following the supplement market closely, you will have seen the first products with a new stimulant on the shelves. 2-aminoisoheptane or DMHA - a supposedly worthy successor to DMAA aka "geranamine" (the stuff in the old Jacked3D) with unquestionable structural similarities to the original banned stimulant and a questionable efficacy and safety profile. With two other non-OTC agents that have been (ab)used to lose body fat for decades, namely ephedrine and clenbuterol, DMHA, which is also called octadrine and correctly labeled "2-amino-6-methylheptane" shares a history as an asthma agent (Monroe. 1947).

DMHA will be banned, when this article is a SV Classic and caffeine again the stim of choice

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Aside from the previously cited study by Monroe et al., a study that showed weak, but existing cytoxic effects in cancer cells by Craciunesco et al. from the early 1980s and an old safety study in rodents and guinea pigs by Fellows (1947), which allows us to estimate the "safety range" of the agent at a human equivalent roughly < 400mg (in rodents, the equivalent dose will already trigger tremors and sign. increases in activity), there's unfortunately no scientific evidence to prove that the agent is (a) safe for human consumption and/or (b) even works as it is supposed to.

Whether the active substance in Eskay Oralator inhalants from the 1940s is a legitimate successor to DMAA can thus only be answered based on speculation and information from the first users, as well as the fact that the agent ended up on Rasmussen et al's recently published list of "novel stimulants in supplements" that are supposed ot "substitute for recently successful products based on ephedrine and amphetamine" (Rasmussen. 2015 | see Table 1 #8).

Table 1: Trivial and chemical names of the compounds supplement companies have dug up in articles from the 1940-50s to replace banned substances in their products (Rasmussen. 2015).

So let's look at what we have: The obviously unreliable user feedback is positive and in line with the implications of the fact that DMHA shares the same structural characteristics which allowed DMAA to interact with the trace amine associated receptor 1 and modulate dopamine and norepinephrine by increasing their production and reducing their reuptake.

Figure 1: It is not difficult to see the structural ressamblance of "geranium" or "geranamine" aka "DMAA" (found for ex. in the old "Jack3D") and "octadrine" aka "DMHA" (as it is found in supps like "InfraRed") when you compare the two.

The structural resemblance to DMAA (see Figure 1) is yet not the only thing the two agents with similar acronyms have in common. Another one is the lack of compelling scientific evidence of their efficacy and safety: Just like DMHA now, DMAA had no no real scientific backup when it first appeared on the radar of the average supplement junkie and it still blew many away - in the positive sense of being happy w/ the results,... at least until the stimulant effects wore off and the crash turned the positive into similarly negative feelings.

Remember the craze about tainted charges of DS Craze with more than just dendobrium | read more

Speaking of supplement junkies... in view of the facts that corresponding products are already on the market, we are certainly going to learn relatively soon about the efficacy and safety of this compound from hundreds if not thousand of human guinea pigs on "the boards" (fitness forums).

Don't be one of those guinea pigs that use an untested product of which I am sure it's going to be banned soon based on hearsay only - regardless of what you hear about purported α-2 receptor activity (like yohimbine) or the fact that it supposedly has similar effects as high dose caffeine or DMAA, but without the crash, by the way | Comment!

References:

• Craciunescu, D. G., et al. "Structure-antitumour activity relationships for new platinum complexes." Chemico-biological interactions 42.2 (1982): 153-164.
• Fellows, Edwin J. "The pharmacology of 2-amino-6-methylheptane." Journal of Pharmacology and Experimental Therapeutics 90.4 (1947): 351-358.
• Monroe, Russell R., and Hyman J. Drell. "Oral use of stimulants obtained from inhalers." Journal of the American Medical Association 135.14 (1947): 909-915.
• Rasmussen, Nicolas, and Peter HJ Keizers. "History full circle:‘Novel’sympathomimetics in supplements." Drug Testing and Analysis (2015).
• Thompson, W.F. - Memo, ‘Low CNS Inhaler’, 22 December 1941; R.S. Fox memo, ‘Disposal of Certain Patent Cases’, 22 March 1942; M.T. Rabbitt to Thompson re ‘Chronologic Report on the Study of Normal-Amylmethyl Carbinamine Sulfate’, 7 June 1945. All in the archives of the California Institute of Technology, Gordon Alles papers, box 15, unlabelled folder.