Excepting the obvious foods I mentioned in my previous post -- soda, chips, etc. -- I'll be charitable and say that it is almost impossible not to eat too many calories in America today unless you are making your meals from scratch regularly. And even then, you have to know to avoid cheese and nuts and so on. That's knowledge that takes a while to come by.
The cooking itself takes time that somebody working a horrible job doesn't have, plus they probably don't have a dishwasher to deal with the mixing bowls &c.