- Messages
- 4,446
- Location
- Suffolk, UK
- Type of diabetes
- Type 2
- Treatment type
- Tablets (oral)
- Dislikes
- Diet drinks - the artificial sweeteners taste vile.
Having to forswear foods I have loved all my life.
Trying to find low carb meals when eating out.
Lots of stuff all together. As usual Internet sites give conflicting information.
All this started off with my increased exercise. Yesterday morning I had a cup of coffee with butter and double cream (bullet resistant coffee) and nothing else then rode my bike for just over 2.5 hours at about 12 mph average. which, of course, gave me far too much time to think. Oh, and I am low(ish) carbing long term.
First off, "hitting the wall":
As I understand it, this happens when all your body store of glycogen has been used up and you can't replenish it fast enough even though you are eating gels and drinking sugary drinks. Around 20 miles for a marathon runner.
If this is correct, then if you don't take on board any sugars/carbs when exercising (or immediately before) you should "hit the wall" sooner? Presumably, also, after "hitting the wall" your body is consuming at least some fats to supply energy?
Given all that presumably I should have been very low on glycogen by the end of my ride, but (apart from tired legs) I seemed to be going O.K. So how do I know if/when I start burning ketones as well as glycogen?
Secondly, glycogen when you are in ketosis:
When you run out of stored glycogen, and you aren't taking on carbs (either through fasting/starvation or an extreme low carb diet) then AIUI your whole metabolism switches over to using ketones for energy. Your brain burns ketones, your muscles burn ketones. However your blood glucose doesn't go down to zero. Gluconeogenesis (?) produces a certain amount of glucose from protein/fat. So far so good - that means you don't get hypos when you are in permanent nutritional ketosis. However it does mean that you are still producing glucose even if it is not your main energy source. So what happens when you are resting after exercise? If you are carbing, your glycogen stores are replenished (liver, muscles and other tissues). However what happens when you are in nutritional ketosis? Do your tissues still slowly store glycogen against future need? Does your liver still dump in the middle of the night? Or do your muscles store ketones instead?
I am resisting buying a meter and test strips to check for ketones in the blood before and after exercise; at the moment I'm just trying to work out in my head what should be happening, and what might happen if I extend a ride by an hour or so. People who are not on a ketogenic diet ride bikes long distance (ignoring for the moment elite cycle racers). Do they learn to stop when glycogen runs out or pace themselves so the rate of glucose uptake matches the rate of glucose burned? Also known as a pub lunch and tea breaks with cake?
Edit: adding a link from another thread courtesy of @Brunneria
http://www.tuitnutrition.com/2016/01/dont-be-a-ketard1.html
Very pertinent to my questions but still leaves a little bit partly unexplained about the maintenance of glycogen stores when "fat adapted". It does note that they are at a lower level because a quick "carb burst" can pump them up again with the associated sudden weight gain.
All this started off with my increased exercise. Yesterday morning I had a cup of coffee with butter and double cream (bullet resistant coffee) and nothing else then rode my bike for just over 2.5 hours at about 12 mph average. which, of course, gave me far too much time to think. Oh, and I am low(ish) carbing long term.
First off, "hitting the wall":
As I understand it, this happens when all your body store of glycogen has been used up and you can't replenish it fast enough even though you are eating gels and drinking sugary drinks. Around 20 miles for a marathon runner.
If this is correct, then if you don't take on board any sugars/carbs when exercising (or immediately before) you should "hit the wall" sooner? Presumably, also, after "hitting the wall" your body is consuming at least some fats to supply energy?
Given all that presumably I should have been very low on glycogen by the end of my ride, but (apart from tired legs) I seemed to be going O.K. So how do I know if/when I start burning ketones as well as glycogen?
Secondly, glycogen when you are in ketosis:
When you run out of stored glycogen, and you aren't taking on carbs (either through fasting/starvation or an extreme low carb diet) then AIUI your whole metabolism switches over to using ketones for energy. Your brain burns ketones, your muscles burn ketones. However your blood glucose doesn't go down to zero. Gluconeogenesis (?) produces a certain amount of glucose from protein/fat. So far so good - that means you don't get hypos when you are in permanent nutritional ketosis. However it does mean that you are still producing glucose even if it is not your main energy source. So what happens when you are resting after exercise? If you are carbing, your glycogen stores are replenished (liver, muscles and other tissues). However what happens when you are in nutritional ketosis? Do your tissues still slowly store glycogen against future need? Does your liver still dump in the middle of the night? Or do your muscles store ketones instead?
I am resisting buying a meter and test strips to check for ketones in the blood before and after exercise; at the moment I'm just trying to work out in my head what should be happening, and what might happen if I extend a ride by an hour or so. People who are not on a ketogenic diet ride bikes long distance (ignoring for the moment elite cycle racers). Do they learn to stop when glycogen runs out or pace themselves so the rate of glucose uptake matches the rate of glucose burned? Also known as a pub lunch and tea breaks with cake?
Edit: adding a link from another thread courtesy of @Brunneria
http://www.tuitnutrition.com/2016/01/dont-be-a-ketard1.html
Very pertinent to my questions but still leaves a little bit partly unexplained about the maintenance of glycogen stores when "fat adapted". It does note that they are at a lower level because a quick "carb burst" can pump them up again with the associated sudden weight gain.
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