Originally Posted by jzbob81
Not quite true either.
That really depends in which "gear" your body is at the time. If you are doing low intensity workout your body will (after depletion of glycogen) use mainly fat as energy source.
But if you're doing high intensity workout your body will tear down muscle mass as it can obtain energy from muscle tissue much faster than from fat.
This is very true. Also........
It is very difficult to do high intensity work while being in a state of losing fat.
I changed my workouts from long steady distance rides where I was constantly in a low state of ketosis and losing 3 pounds per week over about many months to adding quality workouts (intervals) and Brevets. These types of rides need to fueled by gyclogen (at least for me). The interesting result is my weight loss has stopped.
I went from losing 3 pounds per week with no hunger to nothing lost per week and being hungry.
Once I finish the 600k ride, I am going back to my full Paleo diet and long steady distance exclusively.
My fitness has improved doing hill intervals and I am not overtrained but this plateauing on my weight loss goals just confirms what I already knew about my body. I can burn predominently fat at lower intensities and the weight loss is fairly easy. Higher intensities and weight loss don't work for me. YMMV.