I love the 7-day fasts so much!
For me, not eating is very liberating, especially if my day-to-day eating involves lots of carbs. Usually, I try to follow a keto/Paleo/carnivore diet, and if I do, the transition into fasting gets much smoother and easier.
I generally lose a pound per day in weight, not including water weight (which I try to avoid by drinking a glass or two of water with salt and apple cider vinegar). If I'm not under any great stress, I don't get hungry after the first 16-18 hours of not eating and its smooth sailing for the whole week.
Days 5-7 of the fast are usually a high point, I get almost euphoric, especially if I'm consistently meditating. And the biggest payoff is the clarity I feel. I have lots of energy, I tend to get a lot of writing done and I get an urge to go running or play basketball or do something physical.
And the meal that breaks my fast is pure joy:-)
RE: Prolonged