When I was a lot younger, I consciously fasted for 24 hours every Sunday-Monday. I chose those days because I usually had relaxed and nourishing meals on Sat through Sunday late afternoon. Then I wouldn't eat until Monday late afternoon. When I broke the fast, I usually did it with fruit and veg first, then several hours later would eat brown rice with fresh vegetables, sesame seed oil (for flavor and healthy oil) and tofu or salmon. I did that regularly for about five years, then got into a permanent relationship and it made it impractical.
I felt great and I did not have problems with my weight or physique. There have been recent reports that fasting properly can reset the immune system in a positive way. Last week my H and I fasted for 24 hours, as I outlined above. We felt really good, but around mid-morning I had some low blood sugar and slow thinking. But it passed.
We just completed our last meal for today and we'll fast for 24 hours. I went to the store and purchased organic oranges, beets, carrots, ginger root and kale, plus a pineapple and some watercress. To break our fast, I'll juice the well-scrubbed raw beets, carrots, ginger, watercress and kale, then mix it in the blender with the pineapple and oranges, so there will be plenty of pulp. With some cayenne pepper. Then a meal as I mentioned above.
When I was in my 20s, I fasted as long as 4 days, in a supervised way. That was too long for me. I hope we can work up to two or three days, max, because that's what the research says gives the best immune system boost. But right now 24 hours is long enough to start. Skipping meals due to stress is not the same thing as healthy fasting. Research done in the past shows people who fast or go on super-low calorie diets for extended periods almost always end up becoming obsessed with food in an unhealthy way. That's what I want to avoid. If I start fantasizing about food or feeling miserable and deprived, I'll stop the experiment. Don't need to add an eating disorder on top of everything else!
I've had episodes in my life where I could not eat (usually related to grief.) That was totally different. I was emotionally upset, full of adrenaline and cortisol, and not sleeping. Not eating just made things worse. That was not a fast. Not eating in response to emotional distress, combined with not sleeping, made me really sick.
Our goal is to give our immune systems a boost. My husband has recently had cancer -- currently in remission

-- and we just want to be as healthy as we can be.
I'll let you know how this 24 hour period goes.