Telling patients to walk for exercise almost NEVER works!  Studies have shown that most patients who are obese will walk for 30 minutes, then get home and sit for 1-2 hours because they are tired.  They will also eat poor quality food because they are now quite hungry and feel they've earned a treat.  This leads to increased calorie intake with no real increase in total daily energy expenditure - weight gain and a sense of failure.

Studies have shown that you have to exceed 5 hours of vigorous aerobic exercise a week to begin losing weight effectively.  Not many people will commit to that, and luckily there are easier ways!

Resistance training such as weight lifting, dyna-bands, calisthenics (push-ups, sit-ups...) increases lean muscle mass and greatly boosts metabolism.  Muscle tissue burns 70 times more calories than fat tissue, so when you replace a pound of fat with a pound of muscle you make a huge improvement in your metabolism.  It only takes 15 minutes of resistance training 3 days a week to equal the benefit of 30 minutes of aerobic exercise 5 days a week - which would you rather do?

Even better is "interval training".  This is where you  perform a medium-intensity exercise (jump-rope, slow jog, light weights with high repititions) for about 5 minutes, and then do 1 minute of high-intensity resistance exercise such as running full-speed, doing a burst of push-ups or a weightlifting set with a weight you can only do about 8 times before failure.  You then resume your medium or low-intensity exercise without resting, and do another burst of intense exercise in 5 minutes or so.  You can repeat this cycle several times at each work-out.

It has been shown that this form of exercise improves your metabolism far more than any other.  One study compared people who performed a vigorous aerobic activity (jogging, running) for about 5 hours a week to people who did interval training for about half the amount of time.  The people who did the aerobic exercise burned about 3 times as many calories as the interval-trainers, but those in the interval training group actually lost 9 TIMES AS MUCH WEIGHT!  This shows the dramatic effect this type of exercise has on our physiology and metabolism.

If you think about it, interval training is the most logical way for us to behave and therefore the most logical form of exercise.  A natural way of life in the wild would likely consist of steady low or medium-level activity for much of the day, punctuated by brief periods of intense activity such as running after prey or away from predators, fighting over a mate or carrying something heavy.  This is the way our bodies are designed to operate, and once again we see that following a "natural" lifestyle serves us best.

Also, it is important to KEEP MOVING as much of the day as possible.  If you don't have to sit for an activity, then stand!  If you're in the kitchen doing the dishes bend your knees a little and engage your big thigh muscles so they burn energy and get stronger.  Stop making things easier for yourself!  Park farther away, take the stairs instead of the elevator...it all adds up!  One study showed that people who "fidget" all day (those annoying little movements people make when they can't seem to just sit still!) burn up to 350 more calories a day than people who tend to sit more still.  That's an extra 35 pounds of fat each year those people burn without even trying!

The bottom line is - you have to get active in one way or another.  The day-to-day activities all add up, interval training is the best 'bang for your buck', and you have to find something that you enjoy and will actually DO in order to be truly successful.  Don't look at it as a short-term thing, rather as a permanent lifestyle change.  If you 'diet' and 'exercise' for a little while to lose weight, and then go back to the habits that made you heavy in the first place - what have you truly achieved?