That is not a silly question. In fact, it is a very difficult and complicated question.
To start with, are you familiar with the different fuel sources of exercise?
This is rather simple and quick explanation:
how-does-my-body-fuel-exercise
But it’s a bit more complicated when people start looking at weight loss.
If you run slower, yes you are burning more fat than muscle glycogen. But you are also burning fewer calories than if you were to run faster.
As you speed up, your body becomes less efficient. You burn more calories per minute when running faster. But…you can’t keep going as long.
So I guess the best way to answer it is that there is a trade-off. Slower means you burn more fat than muscle glycogen, and you can go longer. But you are not using as many calories. An hour at 11:00 pace (or even a walking pace) means less calories burned than an hour at 8:00 pace, but a bigger percentage of fat. Not more total fat, just a bigger percentage compared to muscle glycogen.
Ultimately burning the most calories is the way to lose the most weight in the long term.
So finding the best weight loss pace for a particular person really depends on how long they can run.
If you want to get awesome real and serious professional coaching, I can hook you up with someone. I think it is money well spent for any diabetic who wants to run.
If not, I can help you with a more generic formula to find a good heart rate that would probably help you burn fat at the most efficient rate.
Or if your interest is in getting faster, and maybe entering some races for fun, let’s get you hooked up with that too.