After a failed attempt at VLC for about 15 days I pigged out on $hit for 3-4 days (it was Christmas time - lots and lots of cookies...). I felt horrible. No energy, muscles were achey. I felt weak. I was also retaining A LOT of water and my whole body just felt like it didn't fit in my skin. I couldn't make a fist because my fingers were so puffy. That was a bad re-feed Since then I've haven't had any multi-day stretches of crappy eating (nor did I stick with VLC - I'm usually in the 100g/day range). However, I've had many single meals of crappy eating and I almost always get really bad calf cramps when I'm lying down in the evening on those days. I have my own cockamamie ideas to explain my observations but they are probably best not aired in a public forum
So, yes, I have experienced this but no, I have no idea why Maybe someone smarter than me will!