Week 2 mega-blip ruined a 5lb loss, turning it into a 1lb loss instead.
Week 4 sausage-blip didn't seem to have any effect...or did it? No idea. Lost 3lb, but could it have been more?
Its not 'fat' weight if you do go up - you simply can't eat 3500 cals x however many lb you gain in that short space of time. You probably only ate a few 100 cal of wine gums, after all. But you can retain water, plus the weight of the food, plus throw yourself out of ketosis, and thus slow up the 'fat burning'. Why would the body burn fat when its got jelly babies/sausages to live on, after all?!
Shouldn't affect you too much - but its a slippery slope, so that's why I've publicly committed to NOT doing it! (This week. Small goals and all that)