15As an avid disciple of the iron, you probably go the extra mile to ensure that your diet is spot on (right?). Or maybe even if you have the occasional cheat meal turned-cheat-day, there is probably one cardinal sin that you would never commit- consuming high glycaemic carbs.
But what if you found out that dextrose; made from corn and chemically identically to glucose, could turn your post-workout protocol on its head, and in the process, enhance your recovery?
You’d be very likely to take advantage of it, we’re sure, why is why in this article we’ll be addressing why you should be adding dextrose to your post-workout shake.
Why Dextrose Is Important
Under normal circumstances, the body’s primary source of energy is glucose, which also happens to be fast digesting and absorbed. The body uses this energy source in the production of adenosine triphosphate (ATP), otherwise known as your “energy currency”. But enough about what it does under normal circumstances. Time to see what is does when consumed post-workout.
Dextrose Refuels Muscle
Even though dextrose is essentially glucose, you may not have appreciated the fact that it does not necessarily stay elevated in the blood for hours on end. Rather, following consumption, the body immediately uses the free glucose it needs to meet its requirements, and subsequently proceeds to storing the extra as glycogen in muscle and liver cells.
These muscle glycogen stores are paramount to exercise capacity[i]. During exercise, your muscles utilize these glycogen stores to liberate free glucose that in turn fuels your workout session. This is why it is critical to refuel with dextrose following your workout.
Ensuring you restock muscle glycogen stores means that your next workout will not suffer because of impaired fuel tanks, and as a result you are rewarded with an enhanced capacity to lift before muscle failure ensues.
Dextrose May Enhance Muscle Protein Synthesis
Muscle protein synthesis (MPS), is the Holy Grail every bodybuilder or strength athlete is after. Essentially, this dictates whether you gain muscle over the long term, as an accrual of muscle mass occurs when the rate of protein synthesis exceeds that of protein breakdown.
A study published in The American journal of physiology, regulatory, integrative and comparative physiology in 2010[ii] sought to investigate if the consumption of 20 g essential amino acids (EAAs) and either 30 g or 100 g dextrose would enhance protein synthesis.
The findings confirmed that there was a significant increase in post-workout protein synthesis for both groups, along with a small degree of impaired muscle protein breakdown.
It is also important to note that the combination was administered within 1 hour post workout to take advantage of the greatest rate of protein and glycogen synthesis during this time period.
Dextrose Can Assist With Muscle Sparing
Know what’s worse than keeping the muscle status quo? Losing muscle. But this is what inevitably occurs following intense exercise, and which is exacerbated if proper post workout nutrition is not employed.
To confirm the fact that dextrose helped with protein sparing, a study was conducted which administered glucose at a rate of 0.88 g/ kg/hr, to adults using a treadmill over the course of 3+ hours.
The findings confirmed that glucose impaired the rate of protein breakdown and nitrogen excretion[iii], both indicators of muscle loss and not conducive to athletic endeavours.
Dextrose Stimulates Insulin Secretion
It’s no secret that consuming carbohydrates of any sort elicits an insulin response, but the sheer speed of dextrose’s absorption sets it apart. During the post-workout period, timing is everything.
Insulin is a highly anabolic hormone, and one that is rightfully referred to as a storage hormone. This is because many of its actions relate to storing nutrients- primarily carbohydrates, in suitable cellular space.
Following your workout, nutrients, namely glucose and amino acids, are preferentially shuttled into hungry muscle cells to initiate recovery, as opposed to the liver or fat cells, two other sites insulin also sends nutrients to.
Insulin also shuts down catabolic processes at this time, bringing protein degradation to a crawl and reducing energy expenditure.
This is why adding dextrose to your post workout protein shake works so well. Not only is a greater magnitude of insulin secretion[iv] achieved, but also a faster onset of action and longer duration of activity.
How Much Dextrose?
While it may seem common sense to assume that a larger amount of dextrose consumed post workout would yield superior results, this is not necessarily true. In fact, unless you are a competitive super endurance athlete, the need for a massive amount of dextrose is not advised.
Studies have been done comparing the consumption of amount between 30-100 g at the post interval window, and there are really no significant differences observed. Thus, it may serve you best (depending on your physique goals) to limit the consumption at this time to 30-60 g.
Stacked with a protein powder, a ratio of 1.5-2:1 (dextrose to protein) works well, and is enough to not cause a significant calorie burden.
Dextrose is cheap, sweet, and highly effective. There aren’t many post-workout supplements that deliver such a bang for your buck, and yet, it is often overlooked altogether.
The next time you work out, add some dextrose to your post workout protein shake for a sure way to enhance your muscle gain and take performance to the next level.
[i] W J Evans, V A Hughes, Dietary carbohydrates and endurance exercise, The American Journal of Clinical Nutrition, Volume 41, Issue 5, May 1985, Pages 1146–1154, https://doi.org/10.1093/ajcn/41.5.1146
[ii] Glynn EL, Fry CS, Drummond MJ, et al. Muscle protein breakdown has a minor role in the protein anabolic response to essential amino acid and carbohydrate intake following resistance exercise. Am J Physiol Regul Integr Comp Physiol. 2010;299(2):R533–R540. doi:10.1152/ajpregu.00077.2010
[iii] Millward, D.J., Davies, C.T., Halliday, D., Wolman, S.L., Matthews, D., & Rennie, M.C. (1982). Effect of exercise on protein metabolism in humans as explored with stable isotopes. Federation proceedings, 41 10, 2686-91 .
[iv] Komatsu M, Takei M, Ishii H, Sato Y. Glucose-stimulated insulin secretion: A newer perspective. J Diabetes Investig. 2013;4(6):511–516. doi:10.1111/jdi.12094