Every time I comment on one of these threads, I mention how most people don't know about the most fundamental component of weight control: Calories-in calories-out.
And then I get a mass of people complaining that "it's not that simple! x y and z also impact weight!"
I think so much has to do with these two points:
1. Most don't know about CICO.
2. Many who do throw it away as not useful.
We should be teaching this in school health classes. I'm not sure if we are, as I'm from the food-pyramid era which was not even close to useful.
Edit: I went from +7 to 0 in a very short period of time. This isn't me complaining, this is me making my point. People downvote the most fundamental component of weight control, even among a likely more educated than average group of people.