Very interesting. I look forward to reading a summary of your month of eating in, but one thing to be careful of is that because you won't have any staples/basics, you should be planning/ready to spend more than you hope your 'average' costs will be. For instance, olive oil, salt, pepper, other seasonings to taste, can all add up fairly quickly but you'll only need to purchase them every few months, if that. Especially if you find some good bulk food stores, you could stock up on non-perishables for a couple of months: while it looks bad on a one-month budget, it'll look good on a three month view.
It's possible to eat out cheaply and healthy in SF but it requires years of practice (in my experience.) You'll eventually figure out where to go and what to get where based on the day of the week (specials), time of day (portion sizes) and time of the year (seasonal items.)<p>For instance, I just happened upon a place in Mission Bay that makes a custom salad (literally, they make it in front of you) with meat, cheese and two other items for $7.50. This salad must weigh 1lb. It's huge, healthy, a great deal and could be split into two meals.<p>Don't give up!