If you're looking for a healthy take-out lunch near campus, try Homma's Brown Rice Sushi near California Ave.
Homma's Brown Rice Sushi
2363 B Birch St, Palo Alto 650-327-6118
It's a tiny hole-in-the-wall place with only a few tables but it's great for take out if you call ahead first. My favorite to-go item is the Chirashi Donburi.