Hi Nicki! I don't believe there is one exact formula that works for everyone. You need to identify your goals and then follow general fitness guidelines that work toward achieving this goal. If you do not see any improvement at all after 4 weeks of a selected fitness program (meaning nothing at all, no soreness, no weight loss, no slight change in your muscle etc.) then you need to re-evaluate your fitness program. But if you see positive changes(they may even be very subtle) after 4 weeks then you are on the right track. Every 4 weeks you should continue to see greater improvements. Eventually, however, your body will adapt to your fitness program and your results will not come as steadily. When this happens, you will need to make subtle changes to your fitness program(ie: increase lifting weight slightly, or workout an extra day, or increase the intensity on some of your workouts, or add 5 or 10 minutes to each session etc.) This will make your body work hard to adapt to the new demands and once again jump start your results.
I agree that I think 4 to 5 days of cardio is a good choice (vary your cardio activities), to lose weight but I also feel that circuit workouts and heavy lifting are both beneficial in helping to lose weight. I don't think there is a "fitness rule" that supports doing one over the other.
To start, I would say do the weight workout of your choice about three times per week non-consecutively in addition to your weekly cardio workouts. Then you can change things around after 8 to 12 weeks and try doing other types of weight workouts along with your cardio. If you find you prefer one method over another, then make changes within that type of method by changing the exercise order, the amount of reps, the amount of weight, etc.
Good Luck!
