I did some intermittent fasting a couple of years ago that really helped a lot, not just with weight, but with energy post-fast, and resetting my desire for sweets. The most I did was 72 hours, which was tough. Supposedly that's the point where your energy returns, but I didn't get to that point. It's true you're not hungry once your glucose reserves are exhausted and you go into ketosis, but I felt just wiped out physically.

BTW, I've found the fast goes much easier if the two meals before you cut out carbs as much as possible. I'll have a lunch with eggs, and then a big piece of salmon with some grilled onions and walnuts, and then hit the fast. Most of the glucose is already gone from my system when I wake up the next morning, along with that weak, growling faint feel you usually get when your blood sugar crashes.