I can relate to a lot of your experience. I’m a Christian, and while many modern Christians do not or have not fasted, there is a long history of fasting in the Church. A spiritual mentor of mine really taught me about fasting after nothing more than brief attempts at dabbling. After being taught about fasting, I have fasted intermittently, typically for 1–3 days at most, however, early on I was lead to fast — I didn’t know the reason why, and the fast lasted 20 days before I was given the answer and completed the fast. The first 2 days of that fast, I did a dry fast (no food or water), but had muscle pains and my mentor suggested that I should have just been water fasting, and I switched to that for the rest of the fast. I was amazed how after 2–3 days the hunger was just gone and it was not at all difficult to not eat. I was carrying on mostly normal daily activities (including work, nothing strenuous), though spent a lot of additional time in Bible study, prayer and meditation compared to normal.
I got away from regular fasting for several years, but recently had done it a little bit, mainly for the purpose of seeking wisdom and becoming closer to God. Then, about a year ago, I ran across this idea of intermittent fasting — limiting the time you eat each day to a limited time window, usually between 4 and 8 hours, for example, not eating breakfast or lunch, but eating dinner at 5 pm, then perhaps a big snack between 8 and 10 pm. Another version of that is to fast 1–2 days a week (often the “day of fasting” is just limiting calories to 500–600 for the day in these systems). I have been following this (sometimes better than others) using a 4–8 hour eating window, though at times I did not follow it closely. I lost about 20 pounds to start with over about 3 month, and have been hoving there, +/- 5 pounds for over 6 months. I recently have regained motivation to follow this protocol strictly along with limiting calories and have reduced most days to a single meal a day, occasionally 2 (both lunch and dinner). The science behind it seems sound with going at least 12 hours moving you from insulin-based metabolism to ketosis (fat-burning), which gives your cells a break from 24/7 insulin. There are many reported benefits, including most regularly reports of fully reversing diabetes or pre-diabetes, among other “miraculous sounding” health benefits, including better brain function, etc. In my mind, this is just part of how God has designed our bodies, and why fasting is traditionally been a part of the faith.
Now that I have regularly limited myself to eating other than water or black coffee most of the day, my body is used to it and I really don’t feel the need for food constantly like I used to. This process has been slow but with continual progress, and as much of it is winning over psychological barriers (scarcity mentality a part of it from how I was brought up) as it is physical. I’m still overweight at least a good 50 pounds, and this is the first diet/lifestyle change that I have tried that has felt completely sustainable. The weight has started finally dropping again and I hope within a year to meet my target weight, and I am realizing a large number of side benefits along the way.