Hi,

I've got a few specific questions if anyone out there can help me. I've done hours worth of reading but can't seem to find conclusive answers specific to my queries. I apologise in advance for the length of this post but I've got no one who would understand what I'm talking about without saying "no carbs are you mad?!" I've learned a lot from Jeff Volek and Stephen Phinney's studies on performance, plus Peter Attia's own personal experiments.

I'm a competitive runner, I race 5K and 10K with the occasional half marathon and other distances, but my focus is the first two. As a consequence my training is very VO2max and Lactate Threshold based. I'm on the track twice a week where I do all my speed work which would consist of sessions ranging from say 15 x 300m to maybe 6 x 1 mile (plus a 3rd session of similar structure but off-road on grass/trails). All at the highest pace I can sustain to keep them all even, so whilst each individual effort isn't flat out, it's certainly in the VO2max region, so presumably very reliant on glycogen.

Ok so my worries are due to performance and whether this diet is capping my ability levels and subsequent race performance. I've been on strict keto now for about 75 days and I'm fully fat adapted. Blood ketone readings on the monitor have been showing levels ranging from 1.1 to 3.1mM β-hydroxybutyrate so a definite state of nutritional ketosis with no risk of false readings from ketostix.

What I've found is that for my aerobic paced running, long runs and suchlike I feel like I've got an endless supply of energy, I could carry on all day and I'm only limited by the soreness in my muscles from the previous day or morning's session. That is great. BUT I do feel like for speedwork my upper limit has been reduced. For example, last night we did 15 x 300m on the track and even though I completed the session fine, I felt that I didn't have an extra top gear to go into, especially during the last few efforts. I used to ramp up the pace and do an especially fast one at the end, but this time I was struggling to cling onto my club mates to do a 50s last rep, when 3 months ago I could absolutely drop them and throw in a 45s last rep. It seems raw power has been lost.

So a few thoughts:
(a) Every time I run now and feel anything bad like tiredness I instantly think oh it must be my diet and it throws doubt over the whole thing. In the past when I'd be tired I'd just get on with it but now I've got something to blame.
(b) It's the back end of winter, maybe my speed is just low due to the time of year and I'll be strong come summer
(c) Depiste keto being one of the only diets which supposedly maintains lean body mass, maybe I've lost muscle mass from my weight loss, not just fat. I stare at my quads now and think surely they were bigger than that before?! Lol.
(d) I've read from some of the experts like Peter Attia and Jeff Volek that they don't recommend keto for say a 400m athlete as it would reduce their ability due to glycogen depletion, it is better for endurance athletes. Whilst I am actually an endurance event athlete, I use sprint and middle distance for training so I've got a cross over.

So to continue this epic length post, a few questions if you can bear with me a little longer:

(1) Ketosis apparently isn't synonymous with glycogen depletion according to a few experts, but how is that so when the whole way it works for weight loss initially is that you dump out your glycogen stores (plus water) and stay in a depleted state? When you become fat adapted do you just prefer to burn fat/ketones first and then only tap into your glycogen stores when you need to, so for intense exercise? Why would your body have loads of glycogen and not use it in front of fat/ketones?
OR, do you just have very depleted stores but not ZERO stores and hence I can do most of my speed session but towards the end what little glycogen I had has been burned up hence nothing left for an all out final burst of speed?

(2) I've been reading about CKD and TKD as a way of solving my problems. CKD doesn't make sense to me due to the fact I train every day, so the carb up at the weekend would make me think it wouldn't fit in with the other 5 days maybe. TKD however does sound very promising, from what I gather I basically stay in ketosis all the time apart from having carbs pre and post session which are essentially used for that session only and then I slip back I to ketosis as the carbs are all used up.
How does that work though, surely that doesn't replenish glycogen stores having carbs before a workout, doesn't it take time to digest the dietary sources and then store them as glycogen? So wouldn't I essentially just still have depleted glycogen stores but a load of circulating fuel in the digestive system/blood stream? Is the circulating fuel able to be utilised efficiently enough to be the instant energy my muscles need or would they prefer to have glycogen already in them so to speak?

Sorry for such a long post, I imagine it'll put a lot of people off reading it. I'm basically at a crossroads now whether to keep keto-ing on or to switch to a diet including carbs. The thing is I absolutely LOVE this way of eating, loads of fats and things that are great with no guilt!, so I'm reluctant to change, but first and foremost it's my athletic performance that matters to me. I would NEVER consider going back to the conventional high carb diet but if I had to change I would maybe look at some sort of primal diet including tubers etc as my carbs, or maybe some slow release complex carbs.

Thanks for your time