Hindu here. There are many different fasts for the many different Gods we have. Each fast is different. Rituals are per much the same. Some fasts are one meal a day with no gluten, no acidic, no salt etc depending on what you are fasting for. Not allowed to get up once you start eating. Wash hands while sitting down using a glass of water poured over hands into the empty food bowl/plate (we eat with our hands). A short prayer is said before and after meal.
Muslim here. Will be fasting for Ramadan soon and also fast Mondays and Thursdays (as recommended). I think if you fast for God, you just do it. In Islam religious fasts are dry fasts from dawn to dusk and I find because it’s for God, I tend to do better because of the discipline involved and lose weight too. When I fast ‘normally’ as in 16:8 I’m more lax and allow things (like insomnia related cravings) to get in the way. Just my 2 cents
Christian here. I fasted for 21 days without a ton of structure besides meditating on the word, specifically scripture that was popping up and repeating as a test/trial got kicked off in my life. I needed some help from the higher power and, with God’s grace, I received it.
Post here https://www.reddit.com/r/fasting/comments/1116o2s/65_male_21_day_fasting_results_2944_to_2566/
Youtube recap here https://youtu.be/5A76VSVMc24
I do it from a gnostic view, so ‘god’ being the higher self inside. I can use the hunger that comes from fasting as a daily reminder to detach from the physical body and it’s feelings. Ingraining the fact the higher being exists elsewhere. Meditation basically
Not that I actually believe in god, but I fast for social reasons during رمضان (or Ramadan in Latin alphabet). You basically have to stop eating and drinking (even water) from sunrise to sunset for the entirety of the month of Ramadan, but after sunset, you can eat or drink whatever and as much as you want. The duration obviously varies depending on your geographic location, but considering that even kids as young as six years old can do it in the scorching heat of Saudi Arabia, it should be quite easy and not require commune with god, though that is still encouraged. Even if you feel tempted to break your fast, social scorn is a very strong deterrent and should stop you long before you even think about turning to god for help.