Ketone Confusion
 

I just watched a video with Glen Finkel & Dr. Eric Westman titled Burning Carbs vs. Burning Ketones. While I am not new to keto, and have read and watched a lot of info on low carb and keto, I don't think I have ever seen the issue of ketosis addressed to my satisfaction. For example, one of the questions in the video was regarding people who start eating low carb and may take several months to start producing ketones. Dr. Westman responded by talking about being fat adapted, but did not really answer the question about not producing ketones for those 2 months. That scenario does not seem very likely to me. I can see where a person eating low carb and not meet the definition of ketosis, i.e. >0.5mmol/l blood ketones, but if they have been eating low carb for 3 months, without the glucose to run on, they must have been producing ketones to keep going. Another example, as I have mentioned before, is my initial weight loss was eating around 80g (estimated) carbs per day, so I doubt I was in ketosis, but I did lose 60 lbs. I would imagine that 60lbs of fat had to be converted to ketones. Anyway, I would like to see some better explanations of what is actually happening rather than simplifying it down to carbs vs ketones, or am I just missing something.

Go to your library and borrow Dr. Jacob Wilson, Ryan Lowery's The Ketogenic Bible: The Authoritative Guide to Ketosis (2017).

I like Amy Berger's three part explanation, though this link also has her new updated one post answer.

Being Fat Adapted Versus "In Ketosis" (Pt.1/3)
http://www.tuitnutrition.com/2016/0...-a-ketard1.html


I am fat-adapted like Amy, the situation described by Dr. Westman.

"Dr. Westman responded by talking about being fat adapted, but did not really answer the question about not producing ketones for those 2 months. That scenario does not seem very likely to me."



My fasting insulin has run between 2-4 for years now, BG is below 100, I am fat-adapted but not always "in ketosis".


Maybe what you are missing is: "There’s an often overlooked but critically important point that rarely gets discussed: free fatty acids.
The body runs on three primary fuels, but we can measure only two of them ourselves. We can measure ketones and blood glucose, but the one that provides the majority of energy in people on ketogenic diets is the one we can’t measure: fatty acids (fats).
http://www.tuitnutrition.com/2017/0...ng-ketones.html

Thanks for the reply and link. I remember reading that a while back. I may have done a poor job wording my post. It is my understanding that we use ketones all the time, even when eating a high carb diet, and regardless if they show up in the blood/breath or urine. I guess what I was trying to say is that is hard for me to accept these people as "experts" when they don't seem to understand this basic concept. I know Dr. Westman understands this, but it seemed that he worded his answer to avoid embarrassing the questioner.

We do use ketones even on a high carb diet, but the absolute values are really low, it's an extremely minor percent of calories burned.


I have kicked this around--dieticians will say our brain "needs" somewhere around 100-120 grams of glucose a day. Other sources give brain metabolism as around 20 percent of total for an adult. For somebody at 2000 calories a day, that gives 400 calories, what you'd get from 100 grams of glucose. Of course this is going to be different for a four foot woman than for a seven foot man.

Anyways--2000 calories low carb...

Give 80 for the popular 20 gram net figure that's going around these days.
Say 100 grams for protein... so we're up to 480 non-fat calories. 1520 calories left for fat, from body or diet. At 9 calories per gram, that's about 169 grams of fat.

Ten percent of the fat is glycerol, you can produce about 17 grams of glucose from that (or that glycerol can be used more directly, decreasing need for glucose or ketones.

The protein--the usual figure is that half to two thirds of amino acids from protein can be made into glucose. So another 50 grams or so of glucose--or even if it never becomes glucose, still a potential brain energy source, either directly, or the amino acids can be used to produce various organic acids that can find their way to the brain and be used for energy.

That's 67 grams of non-ketone glucose substitutes. Add that 20 grams of carbohydrate that's supposed to have you in a ketogenic state as long as you don't go over it, depending who you talk to--we're up to 87 grams of glucose plus glucose substitute. That's already fairly close to the claimed daily energy needs of the brain. So we don't need the brain to secretly be able to burn long chain fatty acids to explain someone eating the low carb diet I outlined without being in very deep ketosis, the stuff's all there, if the metabolism will just cooperate. :lol:

Add that a lot of people will be burning more fat than this (and also more protein). Also add in the fact that medium chain triglyceride not only increases ketosis in the liver slightly--but can also cross the blood brain barrier and make its way into brain mitochondria, where it is subject to beta oxidation and can provide energy. There are little pathways here and there--some scientists actually suspect that humans can produce glucose from acetone, Chris MasterJohn has posted about this, it's not enormous, but small inputs become increasingly important the stricter the diet becomes. Also long chain fatty acids can be used to produce medium chain fatty acids, which as I said can be a more direct brain fuel, and a small amount of even chain fatty acids can be used to produce odd chain fatty acids--odd chain fatty acids can be used to make glucose. It's tiny--like, two 22 carbon fatty acids could be used to produce two 3 carbon odd chain fatty acids, enough to produce one glucose molecule. But maybe these little bits add up.

Teaser,

Thanks for those details. Very interesting information.

I guess I should also admit that I am not sure why I felt the need to write that post. I have recently stopped sweating the details (always subject to change) and just eat low carb without all the weighing, measuring and tracking. There wasn't really anything wrong with that video, but most of them feel more like a sales presentation, looking for views or subscribers, than a technical discussion.

Anyway, I appreciate the reply and the technical discussion.