Longest time is probably 5 days, but ever since I've had limited income I commonly don't eat for 2 or 3 days at a time, it doesn't really start to bother me before then. What's amazing is how much my stomach has shrunk, I used to be able to eat, for example, 4 McDoubles in a row, but I can barely get down 2 without feeling so full that I'm going to puke. This is all partly because I spend most of my money on the weekend or just on weed throughout the week, and I'd just rather be high than eat. More enjoyable, and honestly healthier. I still get all the nutrients I need, minus the huge portions and fat.