I hope this hasn't been covered too many times before, but I'm a bit confused on this

I have been working out (dvds at home - mostly Jillian Michael's 30 day shred) first thing in the morning. I just read though that if you exercise on an empty stomach that you don't have much stored glycogen to use so your body uses your muscles for fuel (obviously not what we want).

Sooo - is this true? And if it is generally true does it still apply on a lc diet, when as far as I understand it we shouldn't have any stored glycogen anyway and should be using body fat for a fuel all the time? And if so - what is the level of carbs at which the switch between the two is made?

Basically - if I eat 50g carbs a day, shoud I eat before I exercise? What about 100g? Or does it really make no difference! And if I should eat, presumably by this theory it should be carbs to replenish the glycogen...

All the research ive seen suggests that being on a ketogenic diet does NOT influence exercise performance.

With the exception of doing heavy HIIT training, you will not waste muscle doing exercise to a greater extent depending on if your glycogen depleted or not.

Also keep in mind that liver glycogen and muscle glycogen are different things. Liver glycogen is responsible for keeping your blood glucose at 5g.

Muscle glycogen is used by Type IIa fibres. And depletes very very slowly compared to liver glycogen, even on a ketogenic diet.

Generally I prefer to work out in a fasted state becuase this increases fat oxidation and I feel more energetic and less sluggish on an empty stomach.

What type of exercise are you doing?

Thanks for the reply! My dvd is fairly high intensity circuits - strength, cardio, abs. Only 20 minutes though.

I have been eating a little higher carb recently (more veggies), so am not sure if I would be in ketosis (I've never tested with sticks).

I'm sure I've read on this site that there is no problem with exercise in a fasted state, but started to confuse myself with the ketosis/glycogen thing!

I do know that before I started lc, I found that I always had to eat before exercising as otherwise I would get very shaky / lightheaded (hypoglycemic I guess) which obviously significantly affected my performance and stamina. On lc I have never had this problem.