Weight loss and fitness will happen at the same time, especially with cardio.
The benefit of 2 shorter sessions, is that you can work out harder for 30 minutes twice a day, than you can for 1 hour. So if total calories, or stress on the muscles is desired, then 2 sessions might be better for you.
If you just want to lose some weight, and breathe better, one session might be better, so you get it done, and go on about your day. It really is about preference. I would hate to have to go back to the gym, or go back out for a run, or a walk. So unless, I take a walk in the morning, and play basketball with friends at night, I tend to get it all done at once.
Just do your 45-60 mins of exercise, whatever way you like, and by burning calories, you will lose weight, as long as diet is right. If you do 2 sessions in a day.. maybe switch up the exercise. That helps with boredom, and works different muscles.
Other than that, I think you are worrying a bit too much about the details. Just move more. The details can come later. Think of yourself as a sculpture. At the start, your goal is to hack of huge chunks without any concern. Near the end is when you will need a fine scalpel to do the details. By then, you will probably also have answers to a lot of the questions, and have a plan for how to take care of these small details.
"We can't solve our problems with the same thinking we used when we created them "
- Albert Einstein
“Whether you think you can, or you think you can't--you're right.”
- Henry Ford
| current weight: 179.6