I know this is contraversial subject and statement, so go easy on me, I am only saying what my own experience has been. I have lost 81.5 lbs in less then 6 months ONLY by changing my diet. I havent exercised at all, except for my job, that isnt very physical (salesclerk in a petshop). The thing I do is to make my digestion do all the "cardio" work. I do that by eating at least 25 -35 oz (600-1000 grams) of vegetables every day, plus 4 fruits, 10 oz (290 grams) of meat/fish, dairy products 8-17 oz (250-500 grams) the amount depends on the amount of fat in them, 2 slices of bread and 0.7 oz (20 grams) of fats and oils. I drink plenty of water with this, and max average bottle of diet-soda pr. day. The only thing I avoid is anything with sugar in it, because it slows the metabolism down. By eating so much of low-calorie food, my metabolism gets into the highest gear and thats why I have been able to lose weight w/o workout. It is not only me that is losing weight doing this, this food-plan is very popular in Iceland, as in other scandinavian countries. If people mention that I have obviously lost a lot of weight, then they also say that their friend/aunt/cousin etc. has lost this and this much lbs, and the numbers I hear about are really incouraging. I admit that NO ONE is losing as fast as me, not even the men. The average weightloss for people on this food-plan is 1-3 or more lbs every week, if they follow the plan.
ps. I am not promoting this plan, only saying it has worked for me and many others. Besides it is only an organization with weigh-in meetings (similar to WW). They are not selling any pills, powders, shakes or any of that stuff. They are just promoting a food-plan that includes very balanced and healthy nutrition, that actually makes you lose weight and makes you much more healthier.