Honestly, there were no side effects other than my back problems went away, I stopped snoring, and I felt better. Even with fasting, I just think your body has enough time to catch up when it's just a pound a day or whatnot. (Btw, you know what the world record for fasting is? 382 days. I'm not recommending that, I like food, but, as long as you get enough nutrients not to get something like scurvy and you consult with a doctor the human body is a lot more adaptable than people realize)
And the time is certainly a factor - people have to set up weight loss scenarios that are sustainable over the long term. My weight loss goal was 1-2 lbs a week, so that was aggressive, but I am large enough that I can lose weight on enough calories to not feel deprived. By counting calories and making sure I had enough to enjoy myself it was a relatively easy process, once I got used to the counting and accountability.
Firstly, fantastic achievement. I'm curious as to what motivated you enough to put in the effort (I'm assuming it required effort).
Secondly, I wonder if the speed/drastic nature of the weight-loss can be counter-productive. When you think about people don't become over-weight overnight. Perhaps a more gradual pace with some time for settling at various stages of the process...I'm thinking losing weight over a couple of years as opposed to over a couple of months.