Fasting

I tried it for awhile and the only thing it helped me with is discipline in avoiding late night snacking. Since I didn’t monitor my food intake I didn’t lose any weight because I wasn’t eating in a deficit in my eating window.

There are a bunch of different kinds of intermittent fasting (some of which I think are better referred to as time-restricted eating, if a special name is needed). I've never heard that any are good for allergies, but it wouldn't hurt to try and see if you have some decent source for that information.

The main types of IFing (or TRE) methods I've heard of are: (1) eating in a shorter time window per day (this is what I call TRE); (2) having 2 days of very low cals (usually something like 500) and 5 days at maintenance; and (3) fasting one day per week (or fasting for 24 hours one day per week) -- this is called intermittent eating by one of the proponents (Brad Pilon).

I've done TRE (or eating in a shortened window) mainly because my current schedule makes skipping breakfast easier and I like eating earlier (not super early) when I'm not spending an hour on the way home from work (as currently) and I never snack anyway. Currently I usually eat in a 7 hour window, although it's okay if I occasionally do not. I find eating two big meals is an enjoyable way to divide up my cals and I have no issues skipping breakfast, have done it off and on all my life. Right now I like that it gives me extra time in the morning to skip it.

All three of the types of IFing I mentioned would be safe for most people (if you have any medical issues, check with your doctor). I don't think IFing is any better for weight loss than any other way of eating (I lost a lot of weight back in 2014-15, and at the time I didn't IF, but ate 3 meals, no snacks, often spread out quite a bit -- 7, 12, and 9 was common). However, I also don't think it's any worse for weight loss -- it will just depend on your personal preference and whether you prefer eating more or less often and in a shorter period of time or not.

The one thing I had to get used to with 2 meals is I've generally used breakfast as a way to get in about 25-30 g of protein, so I initially accidentally dropped my protein and had to consciously make sure to get as much as I wanted in only 2 meals.

I have been doing intermittent fasting for 21 months and have lost 90 pounds. It's been a total game changer for me. It was on my first day on IF and remains so all this time later. I eat between noon and 7:30 pm, with strict calorie counting. I probably eat outside my 7.5 hour eating window twice a month, like when I'm out with friends. I don't make a big deal about it when that happens, but I try to keep it rare. I like this way of eating and intend to stick with it forever. It just really works for me. I had terrible binging habits before I got on the IF bandwagon and this has solved them for me.

Not aware of any safety issues. IF is a healthy way to eat. Your body does not require food in any particular 16 hour period; you'd have to fast much longer than that before questions of safety would even come into play. All of my markers of health, from blood pressure to blood sugar to heart rate have drastically improved, but whether any of that is attributable to IF or is just from losing weight, is hard to say.

It is never a bad idea to chat with your doctor when you have questions about health and safety. If you are concerned, I recommend speaking with your doctor about it.

IF is not much of a diet but rather a schedule of when you eat. You can easily gain weight while doing it.

Honestly, it has been the only thing to really work for my weight loss goals due to how I naturally like to go about my life.

2 days of under 500 calories (not consecutive days). 3 days of MFP recommended deficit. And finally, 2 days of being able to enjoy whatever I want generally.

Doing the standard 7 day a week reduced calories just simply made me feel without all the time. So, switching it up to counting calories over the course of the week instead has really helped.

Obviously, keep it reasonable, keep it something that doesn't create significant discomfort, don't go crazy.

Interval fasting - is that like don't eat really intensely for a bit, then eat slowly for longer, then repeat? ;-)

I've done Intermittent Fasting (or new term mentioned TRE) for years now as the eating schedule (it's not a diet) because I saw some research about improving insulin response for those perhaps going the wrong direction, and potential improvement on migraines if your trigger seemed to be carb related.
And I was skeptical I could do it with my workouts and it would work.

No migraines even during months of no exercise and prior triggers.

Window most days due to schedule and errands and exercise ends up being 10 to midnight.
And even with that window - it is possible to overeat to maintenance - hence it not being a diet, though it may make it easier to adhere to a diet when you can have a nice normal sized meal and treat.

I could never find a good schedule for the 5:2 fasting protocol where the 2 days at 25% of TDEE weren't the day after or before an intense workout needing a good refeed for recovery to do the next one.
And during some times of no workout - just wasn't motivated to test it though I probably could.