Dr William Davis gave a helpful tip. He suggested taking a small bottle of mineral water, drinking some of it, then replacing the fluid with liquid Milk of magnesia. This tops up magnesium levels without overdoing it, when you consume a little of the mixture each evening. Unfortunately Milk of magnesia can deplete the body of potassium, so a couple of dried apricots can redress the balance.
Once again this is useful but not the whole solution.
I had been following Bert Herring's recommendation of restricing food intake to a 5 hour window. Various circumstances led to weight gain despite this regime. I recently wanted to restart weight loss and decided to fast for a day. This was helpful and I continued it for a second day. Not only did I stimulate weight loss and fat burning, but my sleep improved.
I am not an advocate of the 5:2 diet, which allows you to eat anything 5 days a week, but encourages you to restrict calories to 500 or 600 on the other 2 days. I ate nothing and drank only water and herbal teas. The liquid helped me overcome any desire to break the fast and I came through quite comfortably. I count that as zero calories or a real fast. I noticed an absence of other symptoms such as headaches or joint pain that I'd been experiencing in the previous week.
Jason Fung is an advocate of fasting and gives helpful guidance.
When I broke the fast I had a poor night's sleep. That doesn't encourage me to starve myself permanently, but I need to tweak what I do on eating days to improve elimination.
This is an N=1 experiment and may not work for anyone else.