Increasing carbs once fat adapted

(Michael - When reality fails to meet expectations, the problem is not reality.) #41

The hypothesis we sought out to test

A keto-adapted subject (who may already benefit from some Delta G arbitrage) will, under fixed work load, require less oxygen when ingesting exogenous ketones than when not.

The “experiment”

  • A keto-adapted subject (me) completed two 20-minute test rides at approximately 60% of VO2 max on a load generator (CompuTrainer); such a device allows one to “fix” the work requirement by fixing the power demand to pedal the bike
  • This fixed load was chosen to be 180 watts which resulted in approximately 3 L/min of VO2—minute ventilation of oxygen (this was an aerobic effort at a power output of approximately 60% of functional threshold power, FTP, which also corresponded to a minute ventilation of approximately 60% of VO2 max)
  • Test set #1 —done under conditions of mild nutritional ketosis, while still fasted
  • Test set #2 —60 minutes following ingestion of 15.6 g BHB mineral salt to produce instant “artificial ketosis,” which took place immediately following Test set #1
  • Measurements taken included whole blood glucose and BHB (every 5 minutes); VO2 and VCO2 (every 15 seconds); HR (continuous); RQ is calculated as the ratio of VO2 and VCO2. In the video of this post I explain what VO2, VCO2, and RQ tell us about energy expenditure and substrate use—very quickly, RQ typically varies between about 0.7 and 1.0—the closer RQ is to 0.7, the more fat is being oxidized; the reverse is true as RQ approaches 1.0

This is an interesting comment following the table of his results for test #1 while in mild nutritional ketosis alone.

Glucose and BHB went down slightly throughout the effort and RQ fell, implying a high rate of fat oxidation. We can calculate fat oxidation from these data. Energy expenditure (EE), in kcal/min, can be derived from the VO2 and VCO2 data and the Weir equation. For this effort, EE was 14.66 kcal/min; RQ gives us a good representation of how much of the energy used during the exercise bout was derived from FFA vs. glucose—in this case about 87% FFA and 13% glucose. So fat oxidation was approximately 12.7 kcal/min or 1.41 g/min. It’s worth pointing out that “traditional” sports physiology preaches that fat oxidation peaks in a well-trained athlete at about 1 g/min. Clearly this is context limited (i.e., only true, if true at all , in athletes on high carb diets with high RQ). I’ve done several tests on myself to see how high I could push fat oxidation rate. So far my max is about 1.6 g/min. This suggests to me that very elite athletes (which I am not) who are highly fat adapted could approach 2 g/min of fat oxidation. Jeff Volek has done testing on elites and by personal communication he has recorded levels at 1.81 g/min. A very close friend of mine is contemplating a run at the 24 hour world record (cycling). I think it’s likely we’ll be able to get him to 2 g/min of fat oxidation on the correct diet.

An interesting read. Keep in mind, we’re talking about a ‘fat/keto adapted’ individual, not just some guy eating SAD and popping exo ketones.

(Pete A) #42

Back when I started “keto” the first 3 months in my mind I was determined to stay on Atkins induction forever. I hadn’t really heard about Keto. After having twice in previous years lost a good bit of weight on Atkins, when starting those rungs… led to overeating and weight gain.

So yeh 4 years later weight still down, and still doing Atkins induction.

Oh, we call that Keto now? :slight_smile:


Hey @Pete_A
Atkins original 1972 Induction plan was the only place I flourished all thru my low carb journey. In fact, when I hit Atkins Induction from the old version I never ever wanted my cup of salad or my pickle LOL I wanted more meat and more seafood in my life…so that Atkins original induction phase is what MADE me carnivore actually. It was my ‘safe point’ to become awesome and always win vs. every time I tried to climb any ‘carb ladder’ I failed so…I hear ya :slight_smile:

starting the carb ladder and going up those rungs was my downfall actually also…when I learned I had to be an abstainer vs. one ‘who could moderate’ and find a critical carb limit and I had no critical carb limit, mine was like 10g total carbs for the day from my condiments like a tad of low sugar ketchup on a burger or a tad of cocktail sauce with my shrimp…if I even pretended I could go higher, and OH DARN I tried many times :wink: I failed and back to induction and all animal and I thrived again.

I love love love original 1972 Atkins Induction, love reading the old original version of the book and oh yes I read it many times for sure…is it keto now? Nope…it is Atkins Induction plan LOL

key being ‘Keto Plan’ became a plan yet a ‘ketogenic diet’ is out there just as Dr A prescribes thru induction so I think so much of the ‘ketogenic burning body’ can be SO confused by 'following ‘The Keto Plan’ as it goes down :crazy_face:

beauty of that plan was eat ONLY from this list and he gave everyone ‘a cup of salad’ and some limited other stuff like a pickle but Dr A never gave you alot of options ever on that plan…that plan IS ITS’ own beauty ya know :sunny:

3 cheers for Dr A----the original ol’ timey version, not the junkier version they got today…now it is BUY atkins bars and drinks, Dr A sure wasn’t about that ever…so profit and greed screwed Atkins Plan but if you go back, way back to 1972 version and follow that, oh yes we learn so much it is crazy…crazy good :slight_smile:


Great post.

my journey was to find my sweet spot…and darn if that wasn’t the hardest and longest journey to achieve — of course while meandering thru all the ‘insane dieting baggage and ol’ timey nutritional’ crap info out there but if one wants it bad enough, they learn a ton thru their journey and their mini experiments and what works for them…enjoyed reading how well it is working for you :sunny:

(Pete A) #45


(Michael - When reality fails to meet expectations, the problem is not reality.) #46


This appears to be the (or one of the) studies that breathalyzer makers - Ketonix specifically - use to justify their claims about BrAce correlating with overall ketone concentrations and ‘fat burning’.

An interesting study, to be sure. But the unknowns remain: we can’t measure the ratio of acetone to acetoacetate accurately and nor the utilization of acetoacetate/β-hydroxybutyrate compared to how much eventually gets wasted as acetone. What we do know is that generally more acetone means more acetoacetate which in turn means more β-hydroxybutyrate. But we can’t put hard/fast numbers on them. At least I have yet to find a way to do so. Although the study I linked above here is very suggestive.


Despite crushing the acetone myth, I want to thank you for the elaborate explanation, Michael !
I am still way at the bottom of the keto learning curve, and appreciate everyone’s efforts to help the newbies. I am just so eager to find out as much as my brain can handle about keto, and I feel I have found a good place to at least get some honest feedback.
Glad to be part of the breathalizer club ! :slight_smile:

(Michael - When reality fails to meet expectations, the problem is not reality.) #48

Despite limitations, I still utilize my Ketonix simply because it’s a non-invasive measure of something. I continue to search for info to help determine just what that something is and how relevant it is to understanding ketosis and fat adaptation. It’s too bad we don’t yet have a ketone equivalent of a continuous glucose monitor that can track all three in the blood.


Thanks @amwassil ! Will definitely have a look at your links as soon as I have the chance. Meanwhile I’ll just keep tracking and enjoying the experiments :grin: