Sorry, but I don’t quite follow?
It’s easier to build muscle when you regularly provide the body both excess calories and protein – this causes you to bulk up and gain the muscle you want, but also a bit extra unwanted weight.
You then drop the calorie intake but keep protein high preserving your new muscle mass but cutting the unwanted fat
For my zone 2 2hrs 20 mins commute each way to work twice a week, I just use water in the bottles. Trying to avoid sugary drinks on the bike and tune the body to burning fat rather than glycogen. I could be doing this all wrong mind!
That is not a wrong thing to do, but at 4x per week probably being slightly overdone. Maybe do two rides like that and 2 fuelled. Or use water for the first hour and energy drink for the 2nd.
Haha. Now it’s been pointed out to me, I’d say no.
Everyone has loads of fat to burn, even with a very low body fat %.
I’d be looking at your total calorie intake.
At 73kg, including your z3 intervals you are probably burning 600kcal/hr on the bike. 12.5hrs x 600 = 7500kcal. Add your two PT sessions and you are looking at ~9000kcal per week or 1285kcal/day on exercise. Sticking your weight into a BMR calculator along with average height/age came to a BMR of 1670kcal/day.
This leaves you needing ~2950kcal/day, which from what you’ve posted it doesn’t look like you are getting close to.