Here's the paradox. HIIT is slightly superior to LISS for fat loss BUT the former has a higher chance to screw your CNS over. And cardio also affects insulin sensitivity if overdone. It's a double edged sword. but if your diet is dialed in AND supplemented with cardio, BAM! Insane fat loss.

Problem is go too much on a deficit and your body says screw you, I'm retaining the fat. That's why crash diets don't work. Too much LBM loss, and mostly water weight loss. Just like pigging out over the weekend for 2 days non stop, not time to panic yet because most of the gain is water weight, that's the time to go on an aggressive caloric deficit but also don't overdo it.

Your body doesn't want to lose fat. So it get to a reasonably lean state is quite easy, to hit a single digit bodyfat the rules are rewritten. Don't rush it, aim for a loss of 1kg over a week.

If you are in a caloric deficit, your body makes it up by eating itself. Your body gets to choose what parts of itself it is going to eat (fat or lean tissue). It tries to be smart about it and chooses whatever gives you the best chance of survival.

If your body has too much or too little of something, it can usually solve the problem with a conversion. Need more glycogen, then convert some protein into it. Too much glycogen, then convert it into fat.

The preferred fuel for most of your body is glucose. Just about everything runs fine on it. However, your heart doesn't. It runs on a mix of glucose, fat, and ketones. So your body produces ketones all the time because your heart has to have them. 25% of the fuel for your brain has to be glucose. So there is always going to be some in your body, even if your body has to convert something else into it.

The secondary fuel for most of your body is fat (free fatty acids really). Just about everything runs fine on fat. However, your brain and Type II muscle fibers don't. They need glucose or ketones. That is why weight lifting really sucks on low-carb diets. You just don't have enough glucose to use your Type II muscles effectively.

Another fuel for your body is ketones. Just about everything can use them, but except for your heart, they normally don't. They will when your ketone levels first start rising, but after a while they stop and let your brain have it all (both the glucose and the ketones).

Being in ketosis means that your body is making more ketones than it normally would if there was plenty of glucose available. So the definition of ketosis is having an elevated level of ketones.

Considering that your body can only store about 1 days worth of glycogen, elevating your ketone level is a pretty easy thing to do. Just stop eating carbs and it will elevate.

How much it elevates depends how much fat (dietary and body) your body has available and how willing it is to use that fat for this purpose. Your body is also really good at converting protein to glucose. It doesn't have to make up the entire carb deficit with fat, and if you are lean it won't.

That is why keto diets stall out when people get to an average level of fatness. Once your body gets to a fat level it is happy with, it starts cutting back on the amount of body fat it is going to turn into keytones. If you are doing the normal eat as much as you want keto diet, you just eat more and your body uses dietary fats/proteins to make up the carb deficit. So instead of naturally eating at a deficit, you start naturally eating at maintenance and your weight loss stalls.

At this point, if the keto person restricts their calories, then they usually end up skinny-fat. A lot of their weight loss will be muscle.

You can encourage your body to keep your muscles if you use them. Not in a cardio way (it doesn't take much muscle to do cardio) but in a strenuous way (like weight lifting). However, as we mentioned earlier it really sucks trying to do anything strenuous when you don't have enough glycogen to power your Type II muscles.

That is where CKD comes in. You carb load, which refills your glycogen stores so you can use your muscles to encourage your body not to eat them. If you carb load around your work out, then that will make it easier to build more muscle. Now you are doing TKD.

Then after the carb load you switch back to a keto type diet to help control your hunger while you are resting. Will that elevate your ketones? Yep. To keto diet type levels? It depends, maybe, maybe not. Do we care? Nope.

We don't really want to waste our glycogen doing a bunch of cardio before our next weight lifting session. However, stuff like waking and other LISS activities don't really use a lot of glycogen, so doing that is fine.

Also, if you eat a lot of protein it will help keep you feeling full (because it's hard to digest) and if your body needs glycogen it will convert your dietary protein to glycogen before it converts your muscles to glycogen. So having extra dietary protein is a good idea.