Well-planned meals and snacks are critical to a successful conference. However, don't try to do this all on your own. Unless the conference is very small, or the food event is very simple, you should find someone other than yourself to take care of meals and snacks. Consult with your campus food services, or with a local caterer, determine what is needed, and what it will cost. If you're fortunate enough to have extra staff, some of the preparing and serving could be assigned to them. Otherwise, let food services or the caterer do the work. (Be aware that some campuses have policies that allow only campus food services to cater meals that occur on campus.)
Be sure to negotiate food services in such a way that you are not liable for food costs beyond what you can cover through conference fees. Usually food planners will allow up to 10% more people than you contract for (e.g., for late registrations), but be sure this is clear up front.
To reduce costs, seek sponsors for specific meals where possible. Some larger vendors are happy to get the publicity that comes from sponsoring a breakfast, lunch, reception, or even a dinner. Your own college may be willing to sponsor one such event. In any case, it doesn't hurt to ask. If the sponsor desires it, and your campus policies allow it, let the sponsor choose the caterer and take care of the arrangements.
For small conferences, many if not most of the meals can be left up to the attendees. Be sure to provide a good list of local eateries. Include information about which are within walking distance, which are not, and how to get to those that are not.
Strategically scheduled snack breaks, with drinks and fruit or cookies, can add a touch of class to your conference. These don't usually cost too much, and can be covered by registration fees. Don't skimp on the time allotted for breaks, since attendees will want to network and will take the time anyway.
If you do have group meals, be sure to allow for special dietary considerations. Also, work with your campus to determine when (or if) alcohol can be served, for example, at a cash bar reception.