"You actually need healthier food to function your brain and your body to do well in classes," said 5th grader Linda Nguyen.
Now the government wants to make sure all kids are getting healthy meals at school to combat childhood obesity.
First lady Michelle Obama and agriculture secretary Tom Vilsack came to lunch in Alexandria, Virginia school to announce the new guidelines
They include, serving fruits and vegetables every day of the week, more whole grains, and less salt and fat.
They also require schools to serve low fat milk and to limit calories by controlling portion size.
"When we send our kids to school we have a right to expect that they won't be eating the kinds of fatty, salty, sugary foods that we're trying to keep from them when they are at home," said Michelle Obama.
These new rules are the first major change to school nutrition in 15 years. They are aimed at improving the health of the nearly 32 million kids who eat at school.
Castelar Elementary in Los Angeles has already seen results from making their meals more healthy.
Principal Chuck Choi said, "That has made a big difference in our achievement scores and also we have one of the highest attendance rates."
Linda Nguyen says eating right helps her in class to, "We can get a good grade and go to college and get a good job."
The hope is that healthier options nationwide will improve children's appetites for food and for learning.
The new rules aren't as aggressive as the Obama administration wanted.
Congress last year blocked some changes that would have limited french fries and pizzas.