Download Are You Justifying Your Post-Workout Carbs

Are You Justifying Your Post-Workout Carbs?
Dr. Lonnie Lowery
Today I spent about 65 minutes doing my usual chest and arm session. (Yes, it’s fun to
work t-shirt muscles but there’s far more to my schedule and reasoning than that.) I have
moved away from voluminous workouts over the past several years but six sets of
benching, four sets of direct biceps and triceps work, and some accessory / peripheral
exercises did take about an hour. After finishing with abdominal exercises and a few
treadmill sprints, I headed for my usual post-workout drink of 30 grams of a whey-casein
blend and about twice that many grams of carbohydrate (as fruit sugars, sucrose and
starch). It’s not fancy, at least on the surface, I know.
But I digress. While I was loading some plates, I got to thinking that my last workout,
due to life and scheduling reasons, had to be ridiculously brief. In fact, it was only about
20 minutes long. Sad. I’m glad I squeezed it in, but does such an effort require special
nutritional support? Let’s do some simplified math.
If a decent resistance training session requires an estimated 250 kcal to perform, a postworkout shake like I consume resupplies all of those calories, plus about 110 extra. When
we also include about 80 kcal worth of pre-exercise protein (even if it’s not a preferred
fuel), that’s nearly 200 surplus kcal towards muscle growth. Since protein synthesis is
costly – about 2800 kcal to build a single pound of muscle tissue – and everything else is
constant in my life, I’m going to be adding about one-half pound of muscle per week at
best. Of course, this would be a huge homerun for a near-genetic-maximum veteran like
myself, particularly considering the calorie cost of lingering post-workout soreness,
muscle remodeling and hypermetabolism.(3,8)
But what about that pitiful squeezed-in session a few days ago? Well, since 20 minutes is
1/3 of a regular 60-minute session, I spent all of 85 kcal. And since I didn’t get sore
(which would require additional kcal to correct), my usual pre- and post-workout drinks
would place me way over what I would need for weight maintenance and/ or cautious
weight gain at my age. Although it was just one workout, I did notice that I’ve had a fair
number of these lately, perhaps one in five sessions.
But I hate calorie counting. So, let’s focus on the 60 grams of high-glycemic index carbs
in my usual drinks. Many readers are aware that the whole “post-workout carbohydrate
window” was established by landmark studies by the likes of David Costill, John Ivy and
Bill Sherman back in the 1980s, and that boy or girl, carb loading can be effective.(6,7)
Yet I’m coming to realize that not all of my workouts induce such a need. Whether I
obsess over glycemic index, total carb dose or a mixture of the two (glycemic load, if you
will), I just don’t see those carbs being very necessary for a guy like me. Maybe at times
of the year you are similar. When one considers that a decent weight workout will deplete
about 1/3 of his (mostly muscle-specific) glycogen stores,(4) a 20 minute effort may be
demanding only 10% of them. Do I really need to worry about getting-in my usual shake?
There are pros and cons to consider. On the positive side, ample glycogen reserves and
full muscles sure sound good. (Indeed they are, being conducive to anabolism and
providing a 20% reduction in fatigue during longer events and a 2-3% performance boost
in speed-focused events.[5]) Also a plus is the fact that carbs may add a little neurological
or muscular oomph, even in shorter sessions.(2,10) On the negative side, however,
studies suggest that high-carb diets induce lipogenic enzymes.(9) One can crack open any
modern biochemistry text to see this. Carbs may also induce sleepiness if consumed too
far ahead of a workout, if you are anything like me. Insulin is part of the effect and it’s a
real Jekyll and Hyde hormone – permissive on muscle anabolism (and preventive of its
breakdown) but indiscriminate in its ability to store fuels, including fat. After a while,
especially considering that for many people a short 24 hour glycogen load can be maxout one’s muscles nicely,(1) I started to become more and more low-carb… at least
regarding myself.
The bottom line is this: Get introspective and be brutally frank with yourself if your
training logs suggest shorter workouts of late. Training periodization makes this almost
inevitable in the long run. (I sure hope you’re not lifting high-volume, year-round like I
did as a skinny teenager.) Here’s how to see if you are justifying fast-acting carbs, as you
look at your training log…
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Consider the main goal of your current training mesocycle (muscle gain, fat loss
or weight maintenance for in-season performance); some additional carbohydrate
may be okay and even helpful if you’re in a mass gain or performance phase
Ask yourself if your workouts are justifying glycogen replenishment; most
research suggests that workouts should exceed 60 or even 90 minutes to justify
carbs from an ergogenic perspective(2,5)
Be fair and assess whether you have been in hard training for several weeks lately
or you have been more of a twice-per-week “workout enthusiast” - regardless of
how advanced you’ve become in your lifting knowledge (knowledge does not
equal physical need)
Be sure to maintain your protein intake (essential amino acids are what you’re
really after) at 6-40grams post-exercise,(11,13) as you add or subtract the carbs.
The same goes for pre-exercise amino acids (12)
Remember that dietary fat choices and amounts can also be nudged up or down,
even if they’re not much of a pre-post-exercise issue.
So be mindful, young Jedi, of your changing training volume and eat accordingly.
Employ this simple concept of nutritional periodization and you will be closer to
mastering the Force… or at least your athletic progress.
References:
1. Bussau VA, Fairchild TJ, Rao A, Steele P, Fournier PA. Carbohydrate loading in
human muscle: an improved 1 day protocol. : Eur J Appl Physiol. 2002
Jul;87(3):290-5.
2. Convertino VA, Armstrong LE, Coyle EF, Mack GW, Sawka MN, Senay LC Jr,
Sherman WM. American College of Sports Medicine position stand. Exercise and
fluid replacement. Med Sci Sports Exerc. 1996 Jan;28(1):i-vii.
3. Dolezal BA, Potteiger JA, Jacobsen DJ, Benedict SH. Muscle damage and resting
metabolic rate after acute resistance exercise with an eccentric overload. Med Sci
Sports Exerc. 2000 Jul;32(7):1202-7.
4. Essen-Gustavsson B, Tesch PA. Glycogen and triglyceride utilization in relation
to muscle metabolic characteristics in men performing heavy-resistance exercise. :
Eur J Appl Physiol Occup Physiol. 1990;61(1-2):5-10.
5. Hawley JA, Schabort EJ, Noakes TD, Dennis SC. Carbohydrate-loading and
exercise performance. An update. Sports Med 1997 Aug;24(2):73-81.
6. Ivy JL, Katz AL, Cutler CL, Sherman WM, Coyle EF. Muscle glycogen synthesis
after exercise: effect of time of carbohydrate ingestion. : J Appl Physiol. 1988
Apr;64(4):1480-5.
7. James AP, Lorraine M, Cullen D, Goodman C, Dawson B, Palmer TN, Fournier
PA. Muscle glycogen supercompensation: absence of a gender-related difference.
Eur J Appl Physiol. 2001 Oct;85(6):533-8.
8. Lowery, Doctoral Dissertation, Kent State University, 2001
9. Mariash CN, Kaiser FE, Schwartz HL, Towle HC, Oppenheimer JH. Synergism
of thyroid hormone and high carbohydrate diet in the induction of lipogenic
enzymes in the rat. Mechanisms and implications. J Clin Invest. 1980
May;65(5):1126-34.
10. Pizza FX, Flynn MG, Duscha BD, Holden J, Kubitz ER. A carbohydrate loading
regimen improves high intensity, short duration exercise performance. Int J Sport
Nutr 1995 Jun;5(2):110-6.
11. Rasmussen BB, Tipton KD, Miller SL, Wolf SE, Wolfe RR. An oral essential
amino acid-carbohydrate supplement enhances muscle protein anabolism after
resistance exercise. J Appl Physiol. 2000 Feb;88(2):386-92.
12. Tipton KD, Rasmussen BB, Miller SL, Wolf SE, Owens-Stovall SK, Petrini BE,
Wolfe RR. Timing of amino acid-carbohydrate ingestion alters anabolic response
of muscle to resistance exercise. Am J Physiol Endocrinol Metab. 2001
Aug;281(2):E197-206.
13. Tipton KD, Ferrando AA, Phillips SM, Doyle D Jr, Wolfe RR. Postexercise net
protein synthesis in human muscle from orally administered amino acids. Am J
Physiol. 1999 Apr;276(4 Pt 1):E628-34.