To be honest - I don't think people really pay attention to what they eat over the long haul. I agree with what bhsmte said earlier - that there are no people that consistently have a good regimen of activity and eat properly that have a weight problem.
...and I need to qualify what I mean by that.
Prior to 1998, I weighed around 350 lbs. For a variety of reasons in July of 1998 I made the decision I wasn't going to be fat any more. By December of that year I'd lost 150 lbs. I'd done it not through some starvation diet, but rather by going pretty much vegan and exercising every day.
...and when I say every day - I mean every day without fail. There was not a day that I missed.
At the start, I was able to walk about a mile a day. Within a week I'd bumped it up to 1.5. By the week after that, I'd bumped it up to 2. By the week after that, I'd bumped it up to 2.5... Slowly, regularly and without fail I bumped it up to 6-8 miles per day, every day, rain or shine, feeling sick or healthy.
I went vegan, with the guidance of a doctor (although truthfully I could've constructed that food plan myself...like I said...it was basically just a variety of mostly vegetables, fruits, legumes, etc)...and I did not stray from that. There were no cheat days. There were no days that I missed.
That pattern went from July of 1998 until probably around late 2005. For a span of 7 years - there was not a break taken. There was not a day missed. Truthfully, I probably went a little overboard, but I enjoyed lurking around 6-8% bodyfat and the social reactions I got with it.
When I say "how people behave over the long haul" - that's what I'm talking about...and I'd challenge you to find some that can say "I have been completely regimented and doing the right thing every single day without failure since 2008" - not an ounce of "failure" in that mix - and yet they're still obese.
Because it's something that I'm interested in - I pay attention to people - and I see a lot of what you're referring to in an earlier post. They kinda go overboard for a week, weigh themselves, get upset that there wasn't any change (in fact they might have even gone up a pound or two) - they get discouraged - they get off of their regimen for a while - beat themselves up about it - then start again.
That's the kind of pattern I've always noticed. Nobody trusts their body will react the way it should. I truthfully didn't weigh myself until I'd probably already lost about 90 lbs - was curious so I pulled a scale off the wall at Wal-Greens - said "wow" - and then went about my day.
Very very few people have that kind of consistency - and it's that kind of consistency that's required to be truly successful IMHO.
After I got married in 2006 - ehhh - I slacked off a bit and I've gained about 40 lbs of it back over the past 8 years. I'm not particularly happy about it - but I know exactly what caused it. I ceased being consistent in that manner.