Carb Nite® Experiment

There are two themes that run through my mind with nearly all of the reading I've done on nutrition and health the last few years. One is that the most important thing anybody can change in their nutrition to get healthier is to abandon highly processed, "junk" food and eat real food -- as close to what we evolved to eat as possible.  The other, and the one that I've been seeing more often recently, is the idea that there are different, similarly beneficial and successful diets, and that one diet might not be the best for all.  I've also been observing that a change to one's diet (while staying somewhat within the parameters of "real food") might be highly beneficial.

An intriguing discussion of the concept of different, beneficial diets is an article entitled "In Defense of Low Fat"  This is a fascinating, and very long article (I actually extracted it and converted it to read on my Kindle) that I'll cover in an upcoming post here.  It's written by Denise Minger who also is the author of "Death by Food Pyramid."

But the topic today is from a book by John Keifer called the "Carb Nite Solution."  (You can find the paperback version at this link.  You can also find information on a pdf version at  It's about an approach to diet that he developed to help control his own weight and health, and based on extensive research of the literature that he did.

The Carb Nite Concept in Brief

The concept of the Carb Nite Solution® is that a very low carb diet is the best for fat loss, except that when practicing it over a long time, levels of cortisol (the stress hormone) increase and levels of leptin (the hormone that signals sufficient fat reserves in the body) decrease.  By introducing a period of high carbohydrate consumption (about 8 hours) approximately once a week, the theory is that cortisol levels will be moderated and leptin levels will increase.

The other part of this theory is that when you practice a very low carb diet long enough, your body stops making enzymes that convert carbohydrates to fat.  Since you generally don't have an excess, it makes sense that your system for that conversion will be down-regulated.  Because of this, the claim is that when consuming the high levels of carbs on carb nite, your body won't be able to convert the excess to fat.  Instead the carbs will go to reload glycogen stores in the muscles and liver, and the excess will have to be burned off.  This results in an increase in metabolism to burn off the excess fuel.

This is somewhat like the adaptation when one starts a low carb diet. The enzymes needed to burn fat have been down-regulated and take a while to get built back up.  This is why it takes a while to adapt to a very low carb diet.

I find this approach intuitive.  It seems to me that staying on any one dietary approach, in an environment where we can obtain any kind of food at whatever quantities we want (as opposed to the environment in which we evolved -- one of periods of abundance and periods of scarcity) that our bodies will adapt.  It seems that our bodies have evolved to be as efficient as possible with whatever is available, in order to prepare for the next period of scarcity.   The availability might be an abundance of meat and thus protein and fat, or an abundance of vegetables, legumes, and fruits and therefor protein and carbohydrates. Thus, we would hormonally adapt to this monotonous diet and use that food very efficiently.  By disrupting that pattern with periodic "shocks" of high carbohydrate consumption and the resulting insulin spike, we might be able to trigger fat burning and keep our metabolism raised, and be better able to handle the abundance of foods we have today.

In general, there's not necessarily an emphasis on quality of food during these "carb nites."  In other words, there would be a tendency to bring "junk food" back in the diet, if only for part of one day a week.  There seems to be an angle to this diet that the carb nite is a "reward" for all the suffering from what he calls the "severe carbohydrate restrictions" of the rest of the week.  While I currently practice a very low carb diet, I don't see that this as a "severe restiction."  Different from what the typical person today does certainly, but by no means "severe."  I also don't feel the need to have a "reward" periodically.  I enjoy eating foods in a very low carb, high fat, mostly real foods diet.

How I Will Approach This Experiment

A big question as I look to test this approach is how "junky" do I want to make my diet during this experiment?  Do I want to include wheat (bread, pasta, etc.)?  I think I will try this, at least for some weeks just to see how I feel.  Possibly try a few weeks with wheat products and a few without to see if I can see a difference.  Also, since there's an emphasis on spiking insulin, and a view of carb nite being a "treat," sugary products (cookies, cakes, etc.) are suggested.  I probably will experiment with this as well, as much as anything to just make sure I'm getting enough of a blood sugar and insulin spike.

Since I've been on a very low carb diet for nearly four years, I shouldn't have to do anything special for the 9-day "reorientation" period that is prescribed to start the diet.  Instead, I've spent the past few days monitoring myself, particularly with respect glucose levels, to get a decent idea of the baseline I'm starting with.  In doing this, I've been able to recalibrate my diet a bit.  I've noticed, in some cases, meals I hadn't paid as much attention to had more carbs and spiked my blood sugar more than I thought.  (For example, meals that are otherwise low in carbs, but contain breaded dishes, contain more carbs and spike my insulin more than I thought, and I will have to make sure I stay away from these.

How I Will Assess the Results of My Experiment

The primary responses I want measure are metabolic.  Do I improve my insulin sensitivity?  Positive responses would include a lower fasting glucose reading, particularly first thing in the morning. I experience something called the "dawn effect" which is a natural spike in cortisol in the morning creating a spike in glucose.  Despite the time I've been on a very low carb diet, and having a good A1C reading, I still see morning glucose readings in the 100 range.  Daytime fasting readings, 3-4 hours after eating typically are in the low 90s.

I will also be checking my hemoglobin A1C.  I've done the "before" test a few days ago and it was 4.9 -- a good reading.  I will test it after trying the carb nite approach for at least 3 months.  (Since the A1C test is reflective of long term glucose control.)  I'm curious whether the reported benefits of the approach will compensate for the big spikes in blood sugar cause by gorging on carbs once a week.

I've also done a "before" assessment of glucose tolerance.  I've done this test on myself by formulating my own Oral Glucose Tolerance Test (OGTT).  [[I CAUTION MY READERS NOT TO FOLLOW WHAT I'M DESCRIBING HERE ABOUT THIS TEST UNLESS YOU REALLY KNOW WHAT YOU ARE DOING AND/OR HAVE MEDICAL SUPERVISION.  THIS IS PARTICULARLY TRUE IF YOU ARE OR MIGHT BE DIABETIC OR EVEN PRE-DIABETIC.]]  I started with a baseline glucose reading and then consumed 30 gms. of glucose in the form of two "glucose shots."  This is less than half of what a medical OGTT would use, but I felt it was enough to spike glucose and assess my body's response.  It's also in the range of a typical high carb meal (without any fat or fiber that would mitigate the glucose spike) so I felt it was safe for me.  I then tested my blood glucose at about 30 minutes, 60 minutes, 120 minutes, and 150 minutes.  The results are shown below.  I think the spike was good enough to give me a baseline for comparison after I've done the carb nite experiment for awhile.  If my insulin sensitivity has improved I should see less of a spike and a quicker recovery to a baseline reading.

In addition I have a baseline weight and body fat measure that I'll be able to compare to after doing the experiment for awhile.  While weight is not necessarily a direct objective of my experiment, it is a primary target (actually fat loss) of the carb nite diet approach.

Finally, I will see whether I observe the "heat" response the night of the carb nite that is caused by the excess carbs that can't be converted to fat and must be burned.  In addition, the serotonin spike and exceptionally good sleep that is claimed on carb nite.  I'll also assess my overall feelings and changes that I perceive.

As this experiment progresses, I'll update you on my progress so stay tuned.

® "Carb Nite" is a registered trademark of John M. Kiefer and I have no affiliation with him.