Caloric expenditure is not strictly a function of behavior. Holding all else constant, including amount of exercise, reducing caloric intake will also reduce expenditure.

I know, this is why when people stop dieting and return to their original level of consumption, they sometimes end up heavier than before, as Janet mentioned. It's usually better to increase exercise rather than decrease calorie intake, but this thread is about diet, so I haven't really gone into that.

Sometimes it will reduce it by more than the reduction in intake.

Not to say it can't, but I've never heard of this happening. Reference, please?

Once again, it seems I've stated my position badly. I really shouldn't have used the word "simple" in my opening post. Nothing in biology is simple.

I'm not trying to say you can cut food willy-nilly and still be healthy. I'm not trying to use energy balance as a curiosity stopper. I'm trying to use it to combat claims that you can eat as much "good" food as you want as long as you avoid "bad" food.