My first question is why do you feel a need to do 45 minutes of cardio? That much cardio is not needed for general fitness00, thirty minutes of quality cardio twice a week is sufficient for general fitness. Add three days a week of full body strength works, again of 30 minutes duration and you have your workout needs covered.
It is called WORK-ing out for a reason.
I said getting fit was simple, I did not say it was easy.
Cardio burns calories, strength work burns fat.
Eat well to lose weight, exercise to get fit
You can not build a six pack using twelve packs
Often when we seek a magic bullet for fitness we end up shooting ourselves in the foot.
"I think calories are little germs in food that all moms are afraid of" Dennis the Menace