Food is usually the first thing I think of when a need arises. But there are many ways to show you care that don't involve food at all.
A few ideas:
Offer to babysit for a few hours to give a weary mom a chance to rest.
Grocery shop for an elderly relative or neighbor.
Give someone a ride to an appointment.
Teach someone something - to read, how to balance a checkbook, change a tire, etc.
Check out these posts for other ideas...
Write a Letter
Homemade Cards for the Troops
Listen to Someone
Send notes to say thank you
Share Your Hobby
Talk to a Stranger