I posted two articles on training and ketogenic diets that have caused some confusion so I thought I would post the questions and responses for some dialogue.

Metabolism and Ketosis – Protein Power

Ketogenic diets and physical performance – Nutrition & Metabolism

Erik Behan asked a question…

There are a couple points of note in the second article that I think need to be addressed by someone smarter than me.

Resolving the Performance Paradox- Adaptation:
“This adaptation process (keto-adaptation) also appears to require consistent adherence to carbohydrate restriction, as people who intermittently consume carbohydrates while attempting a ketogenic diet (paleo?) report sunjectively reduced exercise tolerance”
To what degree of consumption are they referring to when they say “intermittently consume carbohydrates”? Does this mean by taking in carbohydrates every once in a while I am sabotaging my performance? Even worse so than if I didn’t do Paleo at all?

“Therapeutic use of ketogenic diets should not require constraint of most forms of physical labor or recreational activity, with the one caveat that anaerobic (ie, weight lifting or sprint) performance is limited by the low muscle glycogen levels induced by a ketogenic diet, and this would strongly discourage it’s use under most conditions of competitive athletics.”
Does this conclusion mean I can adhere to a Paleo diet and be an endurance guy but if I want to be strong (weights) and fast (sprints) I need carbohydrate?
After reading the second article I am questioning whether or not the Paleo Diet is legitimate for athletic performance in CrossFit. Clearly it proves that we can benfit from Paleo and Ketogenic diets for overall wellness and health, but maybe not for performance during WODs? I am pretty confused at this point. Someone put me in check please!

A response…

Glad you asked this! Let’s look at this:

1- “Paleo” does NOT necessarily mean “low carb”. This is a simplification that bubbles up from some odd quarters. Paleo is a qualitative approach to eating. The quantities and proportionalities should be an outgrowth of our goals, be they performance, health or longevity.

2-Performance is greatly modified by fueling choices. Will one perform one’s best on a ketogenic diet? Depends on what one is doing. Check out these blog posts.
Yep, there are many of them in there, of specific interest is the one on page 2 dealing with the Zone and athletic performance. What you find from this is a spectrum of people performing at a VERY HIGH levels using a paleo diet, be it low or high carb. They take the time to find their fueling optimum and then run with that.

3-Food quality matters. As I said before, Paleo deals with food quality. What we see again and again, food quality trumps some notion of magic proportionality:
If you notice in Laura’s situation, she went from a vegetarian, Weighed, Measured Zone to an unmeasured Paleo approach (not necessarily low carb) and DESTROYED her previous bests.

4-One size does not fit all. It would be great if some magic proportionality of crap foods could produce elite performance. It can’t. How does one come to terms with all this? READ AND THINK. Experiment, see what works for you. If you look at this troubleshooting guide from Dr. Mauro Dipasquale, the main innovator in cyclic low carb eating you will get a sense of how to make things work for YOU:

So, Paleo is a quality based approach that is not low or high carb. Your carb needs are dependant upon your situation and goals. Low carb approaches are fantastic for leaning out, possibly not the best for all activities for all people. Some kind of cyclic low carb approach is likely a remarkable optimization between performance, health and longevity.


I would not sweat it one way or the other. Lean? Check. Good performance? Check. Played with higher and lower levels of carbs to find an optimum? Check. The statement about ketosis is a bit misleading. Easy ketosis measurements (urine test strips) fail when we are truly fat adapted as we are no longer dumping large amounts of ketones into the urine, but rather using them as fuel. ALSO, one can burn fat like crazy when we have enough carbs in the liver to use as an intermediate in beta-fatty acid oxidation (burning fats in a flame of carbs) but again, this is not the only way this can happen. IF can produce ketones without burning out liver glycogen stores…and IF may be beneficial or antagonistic to performance (health and longevity too!) based upon YOUR circumstances. I do not recommend it to very many people. No one sleeps enough or has a mellow enough schedule to warrant the potential Cortisol action of IF.

Here is a thought: If we actually periodized our training…had a plan and goals, we could shift gears, both with regards to training and fueling, in ways that support optimized performance, health and longevity. You can have it all, you just can’t have it all at once.

then M@, PhD in Chemistry, throws in his 2 cents for some clarification.

I’d like to expand on some of the previous comments. From August 2009 to December 2010, I followed the mains site WODs while doing a ketogenic paleo diet (<50 g of carbohydrate per day). My diet consisted of meat, fowl, fish, seafood, eggs, and non-starchy vegetables (low glycemic index). Strength improved and muscle mass increased while WOD times decreased or stayed the same (i.e. overall improvement in performance). After about 6 months, I started noticing a decrease in performance. First on met cons, then in strength. Mary Conover then brought a research paper to my attention, which showed that endurance athletes on a 30% carbohydrate diet had a lower free testosterone to cortisol ratio (due to lower testosterone) than endurance athletes on a 60% carbohydrate diet. Robb pointed out that the athletes were not given enough time to adapt to the lower carbohydrate diet; a very important criticism that may limit the study’s predictive abilities. If we assume that adaptation to 30% carbohydrate would not have had a full reversal of the observed increase in cortisol (due to increased gluconeogenesis) followed by a decrease in free testosterone, then it seems like my experiment may have been unwise. Sure enough, I eventually hit a wall after a demanding met con (the same wall that endurance athletes hit) and had to replenish my glycogen stores in a hurry (My eyelids were heavy, my eyes were rolling in their sockets, and I was light headed. My brain was essentially low on glucose).
After doing a bunch of research to put together a nutrition seminar (which would never had seen the light of day if Pierre Augé from Capital Strength and Conditioning had not twisted my arm), it became increasingly clear that chronic overconsumption of fructose was one of the major players in metabolic syndrome given that it can only be metabolized by the liver (and sperm cells). Glucose is less problematic given that it can be metabolized by all cells in the body (a lot less will hit the liver).
All this to say that you should modify your carb intake to fit the type of activity that you do. The higher the intensity, the higher the carb intake. Tubers, roots, and bulbs are excellent low-fructose sources of crabohydrates (sweet potatoes, yams, yucca root, parsnips turnips, all varieties of squashes, etc…). Athletes that are very active can tolerate higher amounts of fructose in the diet. Like Robb said, experiment in order to find what is best for you. The post workout window is indeed ideal for a high carbohydrate meal, which will blunt an increase in cortisol secretion.

Comment by M@

Thank you to everyone that contributed to this discussion. Please feel free to email questions on this or any of life’s predicaments.