DAnno's post was great from a fat burning perspective but from a cycling improvement perspective here's my question.
I commute to work monday to friday (zone 1) and spin three times (zone 3) during the week.
Weekends I have 2 long hard rides and my friend is suggesting that I should turn one into a long recovery ride as it will help build my base up, making my body burn fat more efficiently at the lower zones? Is this the best way to go about it or should I maximize my time by going to the longest, hardest rides I can do?