When I look at my immediate family, in comparison I'm a nutrition expert at this point. I shudder to think of what I ate at school growing up - including Taco Bell and Pizza Hut, which were both available in my HS cafeteria, as well as a month-long stint on Slimfast when I was in 7th grade. My mom endorsed that, btw.
My sister, whom I dearly love (when we're not irritating the crap out of each other, as only sisters can do
) has 2 kids. Her older son goes to school with Lunchables . . . pretty much processed junk masquerading as "balanced" food. They eat Hamburger Helper for dinner, and doughnuts for breakfast, and both kids think "nuggets" are a separate food group. But I'm single without kids, and I have no idea what it's like to work full-time and raise kids, so I can't really criticize her decisions - there's no way I could approach this subject without my sister getting defensive. I just hope I can be a good, alternate, example.
I think the USDA and the food industry have a lot to do with terrible school lunches, but I think poor understanding of nutrition has a lot to do with poor packed lunches.