Working out in a natural setting is all the motivation that I need.  Like hiking and, or biking are best for my personal situation.   All it takes for me to get outside is a beautiful day.  The sky can even be overcast, but I will still be out there doing  some form of workout.  This is why for 20 years I have chosen outdoor labor intensive careers like landscaping, gardening, and farming.  These are just a few suggestions from my experience that are the best ways to burn fat.  Getting fresh air is so calming and stress relieving in itself, you can’t go wrong.