Workout question! Is this good?

I was watching the news yesterday while on my stationary bike and it started talking about HIIT. My stationary bike is only pedals. It looks similar to this: a href="http://rehabtime.com/wp-content/uploads/…" rel="nofollow"http://rehabtime.com/wp-content/uploads/…/a except it has a digital display that has the calories I burned on it. So I've started doing kind of a HIIT on the bike. I do 1 minute of super fast peddling forward and then 1 minute of super slow pedaling backwards. I do that for 15 minutes. I seem to be burning about 140 calories doing that. If I pedal normally in 15 minutes I burn around 80 calories. Is it better to do the HIIT version of biking or the normal version?