that doesn't make the weight come back the next day

There's a n excellent place that I've been following for a couple of weeks now, it's got loads of free help and advice and illustrates to you how to lose weight the right way, without dieting. I shed 8 pounds in five weeks by following their helpful advice http://loseweight101.notlong.com

eat half of what you normally eat

How about going for "hunger strike for ever", so you do not have to worry about gaining at all.

Cut out sweets completely, especially sweet drinks, even diet soda.
Drink plenty of water.
Cut out all extra salt on food and don't eat salty foods.
Eat 3/4 or 1/2 of what you normally eat at each meal.
Start eating highly nutritious foods (lean protein, veggies, fruit, whole-grains, low-fat dairy) and watch the weight fall off.
Do 30 minutes of intense cardio each day--60 if you can get it in.
Do some target exercises for your "problem areas."
You can a lot more tips here:
http://www.easy-weightloss-tips.com/targ...

http://answers.yahoo.com/question/index...
Yeah copy and paste if this doesn't come up but, go to my answer this REALLY helped me!

If there was a quick and easy way, then everyone would know about it and weight wouldn't be a problem.