Which is more effective for actual weight loss....riding a stationary bike 4 miles, about 3x per week OR doing a 1-2 mile Walk Away The Pounds DVD, which incorporates knee lifts, kicks, and side-steps, and using light weight balls, about 4x a week? I am really serious about losing weight and just wanted to know which would burn more calories for long-term weight loss. Thanks!

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I would say doing the DVD would cause you to burn more calories. You can increase the intensity of the exercises by performing them faster, which would result in more calories burned. However, you could do the same thing with biking by either pedaling faster or increasing the resistance. The DVD sounds like you will get more of a total body workout and weight training. Increasing muscle mass will increase the amount of calories used. Lastly, riding a stationary bike can get boring, whereas the DVD could be more interesting. When the weather gets nicer, you should try walking outside...much more satisfying.

What your doing is working the heart muscle which does lead to some weight loss but not as immediate as weight lifting. A balance diet combined with aerobic and muscle development will be the best and quickest way for you to loose weight. Muscle uses fat to grow, however too much weight training may also increase your weight (more muscle which weights more). So repetition of low scale weights may be the best solution.

Don't you really mean "fat loss"?
If you're really serious, then just keep up your exercise you outlined.
If you really want to lose fat, then try "calorie shifting". It's not just about how much you exercise, but what KIND of calories you're taking in. Not just how many.
Here's a site that has the calorie shifting program: It's the one that's called "Fat Loss 4 Idiots" and I believe there's a discount.
http://bobs-reviews.com
You can lose 9lbs every 11days...without exercise. Can you imagine how much you'd lose if you did both?!
Good luck,
Robert