You know protein is essential for muscle growth, but carbs play an important role too. Here's what you need to know.
The other day, I was on a phone call with a good friend and fellow strength coach, Joe Dowdell, CSCS, of Peak Performance in New York City. I told him my current deadlift personal record stood at a respectable 420 pounds but that I aspired to pull a 500.
He told me it was "doable."
Great. Then I threw him a curveball worthy of Dodgers southpaw Clayton Kershaw.
I wanted to add 80 pounds to my deadlift … while following a ketogenic diet. Joe let out a big sigh. Staying on a ketogenic diet means eating so few carbohydrates that when your glycogen stores empty, your body cashes-in on a process called 'ketosis' for energy. The carbohydrate threshold to stay in ketosis will vary by individual, but the guideline for most folks is fewer than 50 grams of carbs.
I was dead-set on eating fewer than 20 grams of carbohydrates per day. How low is that? One medium banana would place you over your daily limit!
Wait, don't carbs stimulate muscle growth? How could this work in the long term? More important, can I add 80 pounds to my deadlift without eating much carbs? These questions and more piqued the scientist in me.
So I set out to find the answers not only by poring over the scientific literature but through real-world application on the gym floor as well.
Now before you rush down to the bottom of the article to see if I did it, I want to preface the grand finale by explaining the anabolic capacity of carbohydrates. Let me walk you through several key areas of anabolism in which carbohydrates and insulin play a role.
Carbohydrates, Protein, and Insulin
Carbohydrates create anabolism largely by setting off a cascade of hormone-driven events. (Just so we're clear, you also get an insulin response from protein as well.) Chief among these events is secretion of a hormone called insulin from the pancreas. Many people realize that insulin regulates blood glucose levels, but insulin is not a one-trick pony.
Carbohydrates and the ensuing insulin response have a great deal to do with muscle growth.
It is so multifunctional that many experts believe it to be absolutely integral to muscle synthesis—among other things. For example, one of insulin's many roles is driving amino acid uptake; in other words, it gets amino acids out of your bloodstream and into your muscles.
Thus, carbohydrates and the ensuing insulin response obviously have a great deal to do with muscle growth.
Carbohydrates and Protein Synthesis
When looking specifically at protein synthesis, carbohydrates are not required. Leucine—found in egg yolks, for example—is an essential amino acid and is the primary driver of protein synthesis. That means protein synthesis can occur in the absence of carbohydrates[1-3].
So back to the pressing questions at hand: Is insulin anabolic? Does it help build muscle?
First off, anabolism is often incorrectly used as a synonym for muscle protein synthesis. I encourage you to take a broader view of anabolism beyond the mere combination of amino acids for building muscular tissue.
Anabolism encompasses the entire physiological process that supports muscle building! In that sense, yes, insulin is most definitely anabolic.
Carbohydrates, Insulin, and Recovery
Recovery from muscle breakdown is an oft-overlooked cog in this muscle-building machine. After all, the better you can recover from workouts, the more frequently you can train. Training frequency is a major key player for hypertrophy. Carbohydrates enhance recovery and thus your muscle-building capacity.
While the carbohydrate-mediated stimulation of insulin does not lead to protein synthesis per se, it does reduce muscle breakdown. In essence, the anti-catabolic nature of carbohydrates in turn makes them anabolic. Whaaaat? Remember, you're working to divorce your association of anabolism from protein synthesis.
In that light, carbohydrate indeed is anabolic; it contributes to the whole muscle-building process. The addition of insulin exerts beneficial effects on the dance between protein synthesis and breakdown, called nitrogen balance[5,6].
Carbohydrates also enhance the speed of recovery. During intense exercise, the strength of your immune system is temporarily compromised, but carbohydrates reduce the impact of this immunosuppressive effect and help restore depleted glycogen stores. Whether you should immediately shove a sweet potato down your gullet after training depends on the type of training you're doing, training frequency, and your overall goals.
If you train only three days per week, cramming carbohydrates into your muscles immediately following a workout isn't a priority; your regular carbohydrate consumption throughout the day will help with glycogen replenishment. If you're trying to gain a ton of muscle mass, it probably doesn't hurt to inhale a couple of bananas post-training, independent of nutrient timing.
In my opinion, creatine is a must-use supplement. Whether it is due to its well-known ability to increase strength or its lesser-known ability to potentially improve cognitive function and insulin sensitivity, I recommend you use it every day.
It's known that taking creatine along with carbohydrates increases intramuscular creatine levels due to insulin's effects on creatine transport[12,13] and enhances muscle's creatine storage capacity.
In addition, insulin can enhance electrolyte build-up in cells which, like over-packing the muscle's creatine stores, increases cell volume. Increased cellular hydration and volume both facilitate the kickstart of anabolism.
Anabolism Without Carbohydrates?
After all I've discussed here, it's clear that carbohydrates are anabolic. It's time to circle back to my original deadlift conquest. Was building strength and muscle possible while on a ketogenic diet? Dowdell's sigh notwithstanding, I found that the answer is an emphatic yes!
Don't get me wrong, being ketogenic while training hard was no cakewalk. In three and a half months, I packed 80 pounds into my deadlift and pulled a new PR of 500 pounds on my first attempt.
It turns out that while carbohydrates are anabolic, I am still able to achieve an anabolic feat in the nearly complete absence of carbohydrates. The human body is an amazing machine, possessing the ability to make intelligent adaptations to a variety of situations.
Carbs are not required to flip the protein synthesis switch, but perhaps there are other ways to make the overall anabolic process more efficient and effective.
In a chronically low-carb environment, the body doesn't follow the normal biochemical rules because it has to change. It becomes much more efficient with muscle glycogen, it up-regulates gene expression of certain enzymatic machinery needed for maximum performance, and it adapts as needed to excel in the presence of far fewer carbohydrates and much less insulin.
Quite simply, my adventure in carbohydrate-less anabolism was to prove that you can perform at a high level on minimal carbohydrate—at least in the short term. Carbohydrates are not required to flip the protein synthesis switch, but perhaps there are other ways to make the overall anabolic process more efficient and effective.
Does that mean everyone should adopt a ketogenic diet? I don't think it is for everyone (and perhaps not for the long-term), but it's still interesting to see what your body can achieve through thick and thin.
What are your thoughts on achieving feats of strength while on a ketogenic diet? I'd love to know, so share your comments below!
- Norton, L.E., et al., The Leucine Content of a Complete Meal Directs Peak Activation but Not Duration of Skeletal Muscle Protein Synthesis and Mammalian Target of Rapamycin Signaling in Rats. The Journal of Nutrition, 2009. 139(6): p. 1103-1109.
- Millward, D.J., Knowledge Gained from Studies of Leucine Consumption in Animals and Humans. The Journal of Nutrition, 2012. 142(12): p. 2212S-2219S.
- Paddon-Jones, D., et al., Exogenous amino acids stimulate human muscle anabolism without interfering with the response to mixed meal ingestion. American Journal of Physiology - Endocrinology and Metabolism, 2005. 288(4): p. E761-E767.
- Chow, L.S., et al., Mechanism of insulin's anabolic effect on muscle: measurements of muscle protein synthesis and breakdown using aminoacyl-tRNA and other surrogate measures. American Journal of Physiology - Endocrinology and Metabolism, 2006. 291(4): p. E729-E736.
- WALSH, C.H., et al., Studies in Whole Body Potassium and Whole Body Nitrogen in Newly Diagnosed Diabetics. QJM, 1976. 45(2): p. 295-301.
- Valarini, R., et al., Anabolic Effects of Insulin and Amino Acids in Promoting Nitrogen Accretion in Postoperative Patients. Journal of Parenteral and Enteral Nutrition, 1994. 18(3): p. 214-218.
- Gleeson, M. and N.C. Bishop, Modification of immune responses to exercise by carbohydrate, glutamine and anti-oxidant supplements. Immunol Cell Biol, 2000. 78(5): p. 554-561.
- Jentjens, R. and A. Jeukendrup, Determinants of post-exercise glycogen synthesis during short-term recovery. Sports Med, 2003. 33(2): p. 117-44.
- Rawson, E.S. and J.S. Volek, Effects of creatine supplementation and resistance training on muscle strength and weightlifting performance. J Strength Cond Res, 2003. 17(4): p. 822-31.
- Benton, D. and R. Donohoe, The influence of creatine supplementation on the cognitive functioning of vegetarians and omnivores. Br J Nutr, 2011. 105(7): p. 1100-5.
- Eijnde, B.O.t., et al., Effect of Oral Creatine Supplementation on Human Muscle GLUT4 Protein Content After Immobilization. Diabetes, 2001. 50(1): p. 18-23.
- Steenge, G.R., et al., Stimulatory effect of insulin on creatine accumulation in human skeletal muscle. American Journal of Physiology - Endocrinology and Metabolism, 1998. 275(6): p. E974-E979.
- Green, A.L., et al., Carbohydrate ingestion augments skeletal muscle creatine accumulation during creatine supplementation in humans. American Journal of Physiology - Endocrinology and Metabolism, 1996. 271(5): p. E821-E826.
- Schliess, F., Call volume and insulin signaling. International review of cytology, 2003. 225: p. 187-228.
- Schoenfeld, B.J., The mechanisms of muscle hypertrophy and their application to resistance training. J Strength Cond Res, 2010. 24(10): p. 2857-72.