Relationship between ketosis, fat adaption, and carbohydrates

(mark whittaker) #1

Ok so I am still somewhat confused. I understand that ketosis is when your liver converts fatty acids to ketones when it runs out of glycogen. And being fat adapted is when your muscles have addapted to mainly oxidizing fat directly as a main fuel source.

Is there a relationship between these two functions? or are they completely independent of one another?

can muscles burn ketones? or can they only oxidize glycogen and fat?
if you are fat adapted, is there a metabolic benefit to maintaining ketosis?

I understand that the brain can only burn glucose or ketones. so I assume here that the real purpose of ketogenesis is to keep you alive by supplementing missing glucose for the brain when glucose is in short supply.

but what about muscles? do they use ketones? and if so do they perfer ketones over oxidizing fat directly?

Also. once in a fat adapted state, how do carbs play into fat oxidizing capabilities.

lets say that I am fat adapted and in a steady state of ketosis. The night before a big race I eat a sweet potato along with my buttery steak to add some glycogen to my liver and muscles for some of the large climbing efforts tomorrow.

Two questions about this scenario.

  1. Likely I will be out of ketosis with a sweet potato in my body. But I have been fat adapted for a while so How will this affect my bodies preference to burn fat over glucose?

  2. How does having glycogen stored in muscles affect my bodies preference/ability to burn fat over glucose. Will I truly get the best of both worlds? having a very high maximal aerobic functional threshold (fat adapted) as well as plenty of stored glucose to burn when I need to go above it (hard climb or sprint)? Because that seems like the real benefit here if that is an achievable state.

Sorry I know this was sort of a long and wandering question so let me try to summarize.

I want to reach a state of maximal fat adaption for endurance. But I still want to be able to sprint up a hill or to a finish line.

I am trying to learn how to understand the relationships between ketosis, fat adaption, and carbohydrate consumption.

does my question make sense?

If anyone has any information or can refer me to books/articles/videos I would be very greatful

thanks

(Todd Allen) #3

As I understand it early in the process of fat adaptation the muscles readily use ketones but aren’t yet efficient at directly burning free fatty acids. As the process continues muscles transition away from ketones to more reliance on fatty acids as their primary fuel which spares ketones for the brain lowering our need for glucose and costly protein consuming gluconeogenesis.

I’m not entirely clear on what the effects are of adding carbs back in once one is in a deeply fat adapted state. Apparently muscle becomes somewhat insulin insensitive probably to spare the limited glucose for the central nervous system and RBCs. Many show diabetic level blood sugar spikes in response to a glucose challenge when fat adapted. But muscles still replete some glycogen and some find performance enhanced when adding back some carbohydrate. For more info, search for Dr. Peter Attia’s blog posts on his personal experimentation while fat adapted with very slow digesting starch products for endurance sports.

(mark whittaker) #4

interesting, so fat adaption results in insulin resistance? That does not sound like a good thing. unless I am not understanding something properly.

(Todd Allen) #5

The insulin resistance of fat adaptation is a temporary phenomenon sometimes called “physiological insulin resistance” that resolves over a few days of reintroduction of carbohydrates. It’s quite different from the longer lasting insulin resistance that occurs when the liver, adipose tissue and muscles become choked with fat and become resistant to taking in all energy substrates, primarily glucose but also fatty acids and amino acids.

(mark whittaker) #6

I see. So this almost seems like a highly fat adapted individual eating carbs for a day will not in a short term affect the fat/glucose burn ratio? Especially if they burn them of within 24 hours? would likely be dropped out of ketosis but once fat adapted, ketosis is not a necessary state right? especially if there is blood glucose for the brain?

(Todd Allen) #7

If you want to heavily carb load while fat adapted you would want to do it well before the event because the carbs are likely to drive your blood sugar very high which will result in a big insulin response to bring blood sugar back down. Insulin inhibits the release and breakdown of fatty acids and while high would negate any benefits of being fat adapted. For long duration events where one would like to replenish glycogen on the go without blocking fat metabolism some find slow digesting starch useful. Here’s a presentation that goes into more detail:
https://peterattiamd.com/introduction-to-superstarch-part-i/

(Victoria Mc Coy) #8

How does one know the difference?

(Todd Allen) #9

One can see the difference through testing insulin and blood sugar. Just tracking blood sugar can tell one a lot.

(mark whittaker) #10

Ok so I’m going to try a combination of ucan and some mct powder. For my big weekend ride. We will see what happens.

(Bacon is a many-splendoured thing) #11

It’s a different type of insulin resistance. There is a suggestion that it really should be called “glucose sparing,” because the muscles are allowing the glucose produced by gluconeogenesis to go to the organs that absolutely must have it (certain cells in the brain that are too narrow to have mitochondria, for example). In this state, your HbA1C stays low, even though your glucose levels have risen a bit.

(Jay AM) #13

If you use the search function and look for the exercise section, you should find answers. As I understand it, carb loading isn’t required for non carb burners. Carbs don’t provide nearly as much energy as fat does for the same amount of it and you can’t decide when the carbs will be used either. You can’t tell your body to reserve glycogen just for the sprint for example. We do have runners and bikers here that run purely on fat. They might have good ideas for you if you search for them.

(mark whittaker) #14

yes I have spoken to some of them and they reccomend some carbs if doing a lot of tough climbing. because a 50 minute climb up a mountain is going to use some carbs no matter how you look at it. So I am trying to determine the best way to add those carbs without messing with my optomized fat oxidation.

and I think I may have found it. MCT oil along with UCAN superstarch. I will report on my experience