“No absolute best diet exists; no absolute best diet exists for anyone, but there is an absolute best diet at a specific time for a specific goal.”

-John Kiefer, Author of CBL

I first read Carb Back Loading or CBL back in 2013. It came from a CrossFitter, and at the time, I was in the frame of mind that everything coming out of that camp was lost and unprincipled. Over the last few years my mindset on this hasn’t changed too much, and the devotion with which this group of people tend to hold on to ideologies in the face of research and firsthand experience is disheartening. Nonetheless, I still love the problem of CrossFit and MMA, intelligently building multiple qualities that are in and of themselves generally mutually exclusive.

I also like re-reading books, and over the past weekend, I re-read The Belly Fat Effect by Mike Mutzel, MSc and then got back into Keifer’s Carb Back Loading in the next 24 hour block with a fresh and more open viewpoint. The books are almost the antithesis of each other in recommendations, and each have well over 500 references. If you then take into account The Adrenal Reset Diet, popularized by Dr. Alan Christianson, which somewhat flies in the middle ground of both diets, things get really interesting. How can three very well-known and well-respected authors come up with such different methodologies?

I believe it has to do with assumptions. Mutzel and Christianson are honestly assuming you are messed up. Keifer is assuming you are already a super-hero. One can see the allure of believing you are made of twisted steel and a pulsating onslaught of gains. But is this really the case?

Let’s look at the foundation of what Carb Back Loading is built on – insulin sensitivity and intact circadian rhythms. Most athletes (especially males as we have more lean body mass) who have been at it for some time will be able to take a pounding in the way of carbohydrates, however this is still highly individual (and testable). Yet, to assume that the majority of Americans have an intact circadian rhythm is laughable. We see and say this again and again, but…

“It is estimated that 92% of Americans have cortisol dysregulation.” Sara Gottfried M.D.

If you are living in this country and are a human, you are probably not Batman. If you do or don’t believe the preponderance of evidence that you are fallible, then get an adrenal stress index and a full workup from a functional medicine practitioner. Now most of you (maybe even all CrossFitters) will be in Stage II or Stage III Adrenal Fatigue. It may just be a side effect of our food, environment, and culture. We unknowingly burn out. That is not to say that the stages of Adrenal Fatigue founded by Dr. Hans Selye are the best model, but this is relatively unimportant. What is important is identifying dysfunction and then doing something about it other than pounding pastries.


If dysfunction is present, an even keel approach to carbohydrates consumption is likely the best tactic and there needs to be a good hard look at one’s current lifestyle. On the other hand, crushing the amount of caffeine and incendiary carbohydrates in Kiefer’s plan is probably going to wage war on your HPA axis (Hypothalmic – Pituatary – Adrenal Axis). You may even see results, but at what cost? And will they be maintainable long-term if you have thrown your already taxed body through the wringer?

So I just took away your Teddy Bear of fun carbohydrates and concomitantly told you that it is unlikely that you are healthy enough to indulge in the Carb Back Loading rollercoaster approach. This is because when we knock out the assumption of a normal circadian rhythm and/or adequate steroid hormone balance, the methodology crumbles. If we put these back in, it might have some ground to stand on. But please, please run some tests to make sure everything is in working order before you start inhaling 2,000 mg of caffeine a day and copious amounts of casein and sugar.

I know most of you are like…. “Compromise?! WTF – I want pizza and pecan pie. Pony Up. Go Hard or Go Home!”

I get it.

But let’s look at some other options and collect some data on the situation before we go HAM on some donuts. If you know you are not insulin resistant (favorable HbA1C under <5.3, Fasting Glucose under <83, OGTT score under <120 2hr post) then you are by all means a god among peasants in our country, as it is estimated that 30% of us are pre-diabetic, which is diagnosable insulin resistance. The number of people who are insulin resistant is, however, much higher as metabolic dysfunction starts far earlier than diagnosable pre-diabetes.


Hopefully, congrats 1 for 1.

If you are an athlete, you now have permission to crush copious amounts of items like bananas, sweet potatoes, parsnips, and maybe even white rice. If your training volume is high, you want to first find the range of carbohydrate consumption that supports you; a good range to start with is 30-40%. Space it out throughout the day and make sure to fuel yourself post workout as Keifer eloquently makes the very real case for taking advantage of this window. Not sure how this new Carb life is working for you? Buy a glucometer and test. I’d cover this, but Chris Kresser LAc has wrote the book on it – literally.

Ok, so you have fantastic blood sugar control, and you want to start tweaking things up. You want to tinker, but you got your Adrenal Stress Index back, and there is a lot to be desired. Well first things first, you need to look for food allergies, gut disturbances, environmental toxins, etc. You cannot out supplement a stress-ridden lifestyle or smoldering health problem. Period. It doesn’t work. What you can do is tinker with Dr. Christianson’s “carb back loading” regiment, which he has found to be very helpful with weight loss and adrenal fatigue. He is very good at his job, but the book is geared towards the general population, therefore, athletes will likely need to dial up the food and carb recommendations in his protocol.

The key to success is to collect data, formulate a plan, and then test what worked. I don’t think any of these authors would be against such a methodology. In fact, I bet all of them would want to help and take a peek under the hood.

In fact. I asked Mike Mutzel that exact question

@apacheathlete just curious if you have ever done a podcast or wrote anything on Carb Back Loading. It is coming out from multiple places right now and is the antithesis of your recommendations in the Belly Fat Effect. I think it would be a nightmare for anyone in the general population and most athletes, as we are making a huge assumption in that all the biological rhythms are functioning optimally. We don’t see that in hardly any of our athletes at first. BUT, if someone is running optimally and we know it and have tested it – the ideology is interesting.

@metabolic_mike from a research perspective there was one study in overweight Islamic women that showed more carbs at night altered the circadian rhythm of leptin–but it wasn’t linked with any weight loss. A few studies in endurance athletes have shown no increases in muscle glycogen and actually increases in fat mass. My perspective is you need muscle to get away with eating carbs. In brief–a super majority of ingested carbs are deposited in muscle (~80% of whole body glucose disposal), so if you don’t have a lot of mass for your frame or are not training very intensity, carb back loading will back fire. Could be great if you train really hard like you and I do. But most people don’t push themselves like that. In fact I’ve worked with many overweight folks in a clinical setting and they are already doing carb back loading–little or no food during day and biggest meal at night with lots of carbs–and they struggle losing weight. So my perspective is everyone is different. What works for me may not work for you or others. But for people that don’t have a lot of muscle and need to lose fat, there is simply nowhere for those carbs to go.

End Game – the top tier health practitioners and strength coaches all individualize and follow a data driven approach. You should be no different.

By: Ben House, Ph.D. Candidate, FDN, fNMT