Ate ZC for five months last year. Felt great but as anyone who works out knows, carbs fuel power and fat burning too.
Leangains since then. I eat ZC rest days and 2-300g carbs as taters post workout. Plenty of meat and fat. I eat 2x per day, midday and evening.
Last four months of winter I've been trying to bulk, successfully. Ate more carbs pwo, and added carbs, sometimes a lot, on rest days too, in the evenings. Same foods, meat, veggies, tubers, animal and coconut fats.
Lately, I feel like shit on rest days when I don't eat carbs. I've lost that lovin' fat adapted feelin', whoa that.....you get it.
I also get a bout of feeling super shitty and sleepy (almost a drugged feeling) in the afternoon a couple hrs after meat/fat only lunch.
My protein to fat ratio is a bit high due to the high amount of protein I'm aiming for (2.5-3G/KG).
I read somewhere here that carb flu could entail the body spending more energy on gluconogenesis rather than fat burning ketosis; becoming un-fat-adapted.
Have I done it, that is, can this happen? Can I have made my body burn fat less efficiently due to all the carbs I've been eating? And now, when I don't eat carbs, it's crashing?
If so, I suppose I should do a month fatty meat only and reset.
But I've no intention of staying that way; I need low bodyfat for climbing and carbs for energy replenishment after long ones. So, once adapted again after a reset, are post training leangains carbs just gonna un-adapt me again?
I think you have answered your own question. You say you feel like shit when you don't eat any carbs. I think we need to listen to our bodies true signals some times. Maybe your body is telling you, you need some carbs. Try having 20g a day on your rest days and see if that helps. It is still low carb and then see how you feel on that.
I'm in the same boat, mate! Really dunno what to do. I try carb loading but that makes me feel really tired/sluggish and makes me want to only sleep. But without carbs I feel I'm not that fat-adapted and also I'm just 15 years old, so I need some carbs. Sitting all day at school makes me feel really tired aswell, I try to IF during schooltimes so I don't have to bring 'weird' foods. But it doesn't work really :(
You might look at which meats you have in your rotations. I react very differently to different meats and the only ones that support happy fat-burning are ruminants. Poultry and fish are tasty but tend to leave me hungry and low-powered.
Full disclosure: I'm in my 60s now but I did physical labor and endurance sports for most of my life. I happen to support judicious use of things like bananas to restore energy but that's up to you.