I advise all my friends to do a "one food and work up" diet. I had massive problems with sleep, my skin, my bowel movements, general fatigue, long-onset DOMS after working out - the list goes on. These are completely gone now I pin-pointed the issue. I cut back everything, and added things one ingredient at a time. I started with only root veg, then added legumes, then brassicaceae veg (kale, cauliflower, broccoli etc.) That covered all my nutritional needs bar B12, which I supplement. From there, I've slowly added one more food every couple of week.

My only guess is that I have a histamine response to some kind of compound found in grains and certain types of spices. The body is a strange machination. Honestly, doing the reduction diet was the best thing I've ever done. If you could make a medication that brought me from how I felt 3 years ago to where I am now, you'd be worth more than Bezos.

My wife had struggles very similar to yours. She had herself tested for a super broad range of allergies and intolerances (this wasn't cheap) and found that her histamine levels were 20x the upper bound of "normal". This was in a time when eating a single chocolate chip cookie could knock her out for days.

She then did an elimination diet much like yours (but without the keto - she just cut out anything that either is high in histamine or encourages histamine production in the body). She's a different person now. Her gut mostly recovered in the sense that the same cookie would now make her feel bad for a few hours and sometimes not even that. It's great.

Just in case it interests someone, she maintains a food blog particular for histamine intolerant people at https://histaminefriendlykitchen.com/

It makes sense that histamine messes with sleep. The drug modafinil (Provigil, Nuvigil) is a pro-histamine and considered a nootropic because it reduces sleepiness and even increases focus.

I wonder, can one use a pro-histamine food as a nootropic?

This sounds very similar to Mast Cell Activation Syndrome and it might be worth your time to ask a doctor about it if you haven't already.

Thanks, I'll definitely look into this. I take anti-histamines and aspirin to regulate some of my symptom outbreaks as per a recommendation from my GP, so the fact that it's mentioned as a treatment certainly perks my interest.

for how long did you eat the one food item for? ( is that all you would eat?)

About 2 weeks with 'low risk' foods, and up to 4-6 weeks with 'high risk' foods - low risk being low FODMAP foods, and those that you rarely hear of allergies with. 'High risk' were things like nuts, which many people react very poorly to. I'd add them to the foods I already knew were safe to eat. So for example, I've recently taken to adding buckwheat (which is weirdly a fruit) to my stews and granola after workout. I'm slightly concerned that I may react badly, so I won't add anything new to my diet for a while until I'm 100% sure that it's not causing any under-lying inflammation. I'll mentally keep track of variables like my gym performance, mental acuity, ability to absorb new information, tiredness levels etc. I very much play it by ear though. If I'm especially stressed, or miss workouts, or suffering from any other thing to could contribute to me feeling tired or down, I'll lay off adding any new foods because it will skew 'results'.

There are food allergy tests that you can take, too. I've done the ALCAT test, and it was very helpful. It's a blood test, and provides a big list of red/yellow/green foods.

e.g. Red = likely to cause a strong negative reaction.

I found it to be extremely helpful in finding things that were causing issues.

Kale, Cumin, etc. Things that I would not have easily identified on my own.

I did one of those, and later found out the one I did was pretty non scientific :-( I’d urge caution there

Have you checked for diabetes?

I have, because I’m super super sensitive to sugar, get thirsty a lot, and pee a lot but ... the tests are always normal. Cutting out sugar has made any symptoms go away.