Gatorade and other sports drinks are marketing scams. If you read the nutrition label you'll see a full bottle has barely any electrolytes - you'd have to drink bucketsfull just to reach 50%. The sugar free versions are hardly any better, with artificial additives that can mess with your gut - especially counterproductive as you're fasting to fix gut issues.
You can make your own electrolyte drink with potassium chloride / iodide, sodium bicarbonate, and sea salt. Stick to a ratio of 6:1:1 (mg potassium to mg sodium) if using both latter sources of sodium, or 3:1 if just using potassium salt and regular salt. Figure out how much water you should drink - 1.5L is a good minimum, then experiment to find the intake level where you feel and perform best. Your urine should be pale but not completely transparent.
Take supplements for calcium and magnesium (bisglycinate and its related forms, as well as chelate, are preferable to oxide and citrate). Unless you can find powdered forms of those and wish to incorporate them into your electrolyte drink. I wouldn't advise it. There's a reason they heavily flavour magnesium tablets - the powder tastes nasty.
More is not better - depending on your demographic (age, weight, activity level etc) you will need a certain amount of electrolytes. Below or above that range - especially if out of ratio - for a prolonged period can give you heart problems. I'm assuming you don't have any kidney, thyroid, cardiovascular etc problems already - fasting can be beneficial even for those groups but I'm not qualified to advise for those situations.
But overall, listen to your body. If you feel sick drinking the above, don't force more down. Fiddle with the ratio and drink plain water in the meantime. At this point, I don't measure my electrolytes, I just take a pinch of salts with a swig whenever I'm feeling foggy or dizzy. I keep salt sachets in the car as a prophylactic measure and they serve me well. For someone only just starting out on 24h+ fasts, measuring is advisable. Keep logs of how you feel at what time. Data is always good to have. You can refer back to it when planning future fasts.
I find that when I make sure my electrolytes are in check, I have enough energy to exercise, even after five days of fasting. Stomach aches can be soothed with heat - take a shower or bath, or drink dilute tea if your fast allows anything other than electrolyte water. I tend to get flashes of euphoria - not irritability - but those fade into the daily humdrum soon enough. Note that the longest I've fasted is just over five days and not for gut issues - and anyhow every body and mind is different.
Read The Fasting Fix by Dr Andreas Michalsen. The protocol he uses in the clinic allows up to 500 kcal per day. Snake diet, popular online, is used mostly for weight loss but has good information about fasting as well. Best of luck to you. Let me know if you have any more questions and I'll answer them to the best of my ability.
Edited to add that those who find a thread 'offensive' can click the ignore button. Censorship leads to the downfall of democracy.
