That is interesting and sits well with my current protocol (been keto since last autumn).
Check the recent work by Volek/Phinney: keto-athletes resynthesize glycogen almost as efficiently as athletes on traditional higher carb intakes.
Another interesting theory, but one I have difficulties believing.
Where do keto athletes get their glucose from for glycogen “resynthesis”. If the purpose of IF is to activate breakdown of abnormal proteins, then getting to the point where gluconeogenesis is shut down would not be consistent with the purpose of IF. And any hypocaloric diet will result in breakdown of abnormal proteins and cell destruction. IF is intended to be used for individuals on maintenance or hypercaloric diets to give periods autophagy in the week. (As I understand it).
Although very anecdotal, only yesterday I registered 0.9mml following a blood ketone test. This follows a few days on PSMF, which shows, for me anyway, gluconeogenesis is not nearly as prevalent as some folks claim.
Speculated that it is from lactate and glycerol, which is far higher in keto-adapted athletes. There is also a theory that it may be due to some adaptation where the BCAAs are spared ahead of other amino acids such as alanine, which is highly glucogenic.
I would suggest most folks that do keto embrace IF for far simpler reasons: which is to do with greater satiety making it easier to go without food for longer and cut overall energy intake.
Are these strength or endurance athletes? In theory it could be protein turnover from training muscles. Who are the most notable full time keto adapted strength athletes that you know of? I know that endurance athletes can have fat loaded muscles and still retain full physiological insulin sensitivity. Also probably many bodybuilders.
By the way, it is important to note that ketones and fat loading tend to cause “physiological” insulin resitance by blocking glucose uptake, but ketogenic diets still probably improve insulin receptor sensitivity by reducing insulin exposure. Point is that there are really three mechanisms of insulin resistance: 1) excess of non-glucose energy substrates in muscle, blood and liver which can be physiologically normal or pathological (fatty liver disease), 2) low sensitivity to insulin at the cell receptor level either due to mutations, lack of possible co-factors, or reduction in number of receptors due to over-insulin exposure or autoimmune attack and 3) stress hormone induced insulin resistance.
I think that if people want to improve their insulin sensitivity, it is important for them to assess which of these mechanisms is most likely at play.
That is interesting because I never had a satiety problem on a fat based diet with 25% carbs that was any different in nutritional ketosis. Nutritional ketosis was harder to maintain because the volume and variety of food you can eat goes way down when you are eating calorie dense fat, and when you also have to avoid getting a lot of protein at one time. I found that I was eating a much smaller volume in nutritional ketosis because of the caloric density of the fat.
Endurance athletes, although there are some studies showing equal performance but greater reduction in fat free mass in studies involving gymnasts and taekwondo athletes. Of course, there is little scientific work involving strength athletes.
I am 69th day in the IF mode (I lost almost 15 kg of BW) and I have to say that my muscles have improved, but this is logical, as the body fat was reduced among other things.
I get a little bit of a drop in energy because I have a very low intake of carbohydrates (maximum 30 g per day). This the drop in energy pisses me off.
PS: I’m in the IF mode during strength training.
If you have been on a max 30g CHO for the last 69 days then you should be fat-adapted and ripe for implementing a targeted ketogenic diet, which is simply 5-15g fast acting carbs pre-workout. You should also consider MCT oil (5-15g) with or without said carbs.
Overall, you should not be experiencing such an energy lull on a well-formulated ketogenic diet. This may due to protracted low energy intake? If so, a diet break for 1 week or so at maintenance may assist. Good luck.
That can be an issue. I have become a bit more savvy in the kitchen of late and it is quite amazing what you can conjure up, e.g. curries with cauliflower rice, chicken and egg fried rice usingwith konjac rice, beef Bolognese with konjac spaghetti, etc. Desserts such as low fat cheese (quark) with zero calorie syrups, mug cakes using coconut flour, cocoa, stevia, egg, etc.
Anxiety what’s that…I seriously have to generate my diet to help with my cortisol levels. Plus, I don’t get enough sleep. Really good post 
.
Yes, I’ve lowered my calories because I want yet to lose a few kilos of BW.
I start the ketogenic diet after the IF mode is complete, it was yet unnecessary to mention the ketogenic diet. 