I follow the Body for Life program for exercise - but not for diet. Body for Life is an exercise book by Bill Phillips.
My summary of the Body for Life exercise program is as follows:
1. Do cardio three times a week for 20 minutes at a time. The first minute, start at 50% intensity, then go to 60% for the second minute, 70% for the third, 80% for the fourth and 90% plus for the fifth, then start over again. I usually add another five minutes of cardio cool down like walking or slowly pedaling just to recover...
2. Do strength training three times a week (upper body twice, lower once and then the next week lower twice and upper once). Similar type of increasing intensity as cardio for each muscle group exercise. Start at 50% weight and build up for each muscle group.
I really like the approach in that it appeals to me as an ex high school athlete to work out really hard and intensely. Rather than pedal an exercise bike for an hour while reading this allows me to work REALLY hard for just 20 minutes. I end up covered in sweat after every cardio workout and I get my heart rate way up...
You will absolutely see the benefits quickly. It is hard. Sore muscles aren't fun and sometimes its hard to keep this up, particularly if you don't like to work out. The upside is that my upper body, core and leg muscles are much, MUCH more defined and I have a ton more energy. I actually get a post workout energy high from the cardio. If you combine this with eating well you will become much more fit.
I did find that the strength exercise instruction is not very detailed in the Body for Life book. It is very easy to do the exercises incorrectly which could cause some serious muscle or back damage. So I do think its important to have a good trainer teach you how to do the strength exercises rather than just depend on the Body for Life book.