To burn fat it really doesnt matter which one you do first. The amount of calories you burn depend on the amount of activity over a given time period. Though do keep in mind you have to work out for about 30 min before you even start using your fat reserve, so at the 30 min mark is when you should start counting your true workout time.
I do suggest lifting first then running though. The running will help get the lactic acid out of your muscles, which will help prevent you from becoming too sore. Also running then lifting will strain your muscles to the point where you either A) are too tired to lift effectively, or B) will push your muscles beyond the limit and will get injured.
|