We don't recommend fasting, unless you are being supervised by your doctor and they are recommending it. Here's an Ask the Expert page that addresses fasting: www.sparkpeople.com/community/ask_the_expe
that you may find helpful in understanding that.
As MRSTIGHTWAD mentioned, you can change the intensity levels of your exercise to keep your body from getting used to doing the same things. My concern in using a site like that to determine your workouts, is that you may be doing one or two types much more than the others, so you may be doing too much of a particular type of exercise and not enough of another.