Going a few days w/o much food is quite easy for some of us, -I would skip meals after 1800 in the evening and then skip breakfast and then I could go a few days w/o more than a couple of glasses of orange juice a day. I only did this for less than a week. My uncle said most of the good effects started kicking in after a 3-5 days.

As usual, be careful, I'd say have sugar around.

As for the last point you mentioned there are drugs for this, I just have a feeling you'd rather try without but I'm no expert.