I have had periods of time where I have done a fast a couple of days a week. I have never done it properly on a Saturday - too hard!!! I am probably a wimp though and I always found it hard to do and still fit in with family meals on a Saturday.
Best way to get through it is drink water or the lowest calorie drink you can and think of what you can have tomorrow instead. I used to have flavoured fizzy water, fills you up but no calories and it felt like a treat because I didn't have it the rest of the time.
I find drinking water helps a lot but if its a hungry day I do suffer too. Weirdly, I only ate 350 yesterday and today I've already eaten 1300 (toast for breakfast, fry up with spuds, bacon and poached eggs for lunch. Yum.)
Just keep thinking of the weight dropping off as you fast!
I now love my fasting days they give me clarity I plan my meals for the rest of the week I go veggie for those days (by default - easiest way to hit the 500 while feeling stuffed) had massive sunday lunch today and enjoyed it more knowing that I'll not eat tomorrow.
NB fasting days : pick easy ones. DH and I do Monday and Wednesday / Thursday : added not good for the next 20 years....