What I observed was a discussion of 2 as if it were not really simple.
Would you mind linking to an example so I can understand what you are talking about?
If you make a rule saying you'll not eat carbs, you'd be hard-pressed to come up with enough calories eating non-carb stuff to not lose weight.
That may very well be the case. I myself am pretty skeptical of low carb dieting. At a minimum, it does not appear to be the "silver bullet" which some people have claimed it to be.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.