Our school requires that we buy into their insurance plan. No exceptions unless you are on someone else's insurance (like a parent or a spouse.) But if that isn't required, medicaid may indeed be an option.
Food stamps may be more possible in some places than others. I definitely know a number of college students (who lacked family support for one reason or another) who were eligible, as well as a lot of working poor folks who get them. You don't get very much as a single person, no kids. And you usually need to have a job. Once I was turned down for food stamps because, although I was employed, they said that I wasn't working enough to qualify for food stamps. I was working all the hours that my job would give me, but that was not as much as 20 per week. I lost my housing, and became homeless, but kept my job. I tried again to access food stamps and was told that now, since I didn't have a rent payment, my disposable income was too high for me to get food stamps.
Food banks are an option, and there are usually programs for people who aren't eligible for food stamps, but who still don't have adequate food. They also usually have volunteer opportunities, so that you can do some work in thanks for receiving help.