They only pass on the Doritos when they have a sweet tooth. I can usually resist salty snacks, but I've had to banish cookies and brownies from the house until I can find more willpower. (Sweets are definitely my weakness)
When my kids need a sweet fix, they have to choose between walking up to town and buying something or eating one of my fiber-one bars. They don't seem to realize that the fiber bars border on healthy.
I'm trying to lead by example, but so far, it hasn't worked much. It took my family almost a month to realize that I'd stopped drinking soda.