Yes, if I was eating, say, 2000 calories per day and cut 1000 calories, I probably would lose weight. But anybody who is starving WILL lose weight. I'm not saying that calories don't matter- of course they do in that if you restrict them you will lose weight. But most people can't live that way. So I'm talking about a way that doesn't count calories, because they simply don't matter if you eat the right foods. If you want to lose body fat (not just the actual weight), this is good to know.
My point is that calorie restriction only works in drastic measures. I eat more like 4500 calories per day now- so if I cut 1000 calories per day I wouldn't lose weight probably. That's still not a calorie deficit in the traditional 'dieting' sense. I can eat far, far, more calories and not gain weight but I get full too fast.
If you eat 1500 calories of low-fat yogurt and fruit, diet sodas, etc, and I eat my regular diet of paleo/primal eating (no low fat anything, no sugar, approx 4000 calories per day), I will still burn it off. You may or may not. It really depends on what you eat- people who are on the 'low fat, high carb' diet are simply fatter than people who eschew those 'diets'. My body fat level is pretty low, considering I never formally exercise.
If I go out and have pizza, I gain two pounds. That's not from calories, though- it's from the carbs. If I eat a sauce, and I gain weight the next day, I can ask a friend, "Oh, what was in the sauce?" and they will say, "oh, a cup of sugar..." and I knew it! But if I eat my normal foods, I don't gain an ounce. And I eat a TON of food. Seriously- more than most people could ever fathom.
I know it flies against every single thing we've been taught in the last 30 years! But I firmly believe that we (health care professionals) are killing people in huge numbers with what we are teaching via the food pyramid and the low fat myths.
This is all very oversimplified, as it's not easy to go through all of the biochemistry in a short (or even a long!) post. But the gist is here, and you can do your own research to debunk or prove it:
http://www.marksdailyapple.com/7-common-calorie-myths-we-should-all-stop-believing/#axzz3ShZvWzbb
I'm going to bow out of this thread, as I know this can get contentious. And I'm an admin of a brewing forum, not a nutrition forum and don't want to hurt anyone's feelings.
But everyone who wants to be healthy- do your own research! If you are convinced that you can find complete health by your own means then do it- and don't be disuaded by so-called experts.