Three years ago, when I started reducing medication, I developed serious problems with sleep and restlessness. I had not considered asd at that point, and started keeping food diaries, thinking along the lines of "you are what you eat". It took a long time to pin down the problems, because I was having so many substances that disagreed with me and the effects take hours or days to kick in. The effects were also masked by the medication I was taking, which made me sleep 9 + hours per day. These are not allergies, more intollerances.
I have continued with this on and off, since then, and thought I would share my findings with you, in case they help anyone else. I realise that we are all different, but some of my issues may affect others.
Caffeine is a complete no no for me. 1 cup of coffee can keep me awake for 24 hrs. I now avoid even the smallest amounts, so basically I have to avoid coffee and tea, (including decaf) cola drinks, chocolate, (I have tiny amounts, early in the day) and non-drowsy medication such as pain killers, cough medicine, antihistamines.
Chocolate is an issue in it's own right. You may have heard that it is poisonous to dogs and cats, well, some humans are affected too, particularly by high cocoa chocolate, such as dark chocolate. It gives me severe palpitations.
Artificial sweetners make me agitated and alert, some time after eating them, often in the night. Any issues I have are accentuated and more inclined to keep me awake. It is relatively minor, just annoying. I was caught out recently by some free vitamin c tablets. I have to avoid all "diet" soft drinks, "no added sugar" soft drinks and many types of over the counter medicines, such as cough medicines, vitamins, and some sweets etc. I can use the natural sweetner stevia, which is made from the stevia plant, I assume because it is a natural sweetner like sugar.
Flavour enhancer, AKA monosodium glutamate, is another problem. Again it causes palpitations, which rob me of sleep. It is in many processed foods, including some burgers, sausages etc. I have even been caught out buying burgers from a farmers market, assuming they would be better, but some add burger mix to their burgers, which contains msg.
My final issue is dairy products, which cause itching, if I have too much. I assume it is mild eczema, as often there is nothing to be seen in the affected area, but it can play havoc with sleep.
I believe many people with asd seriously over-react to substances which most people can eat with no effect. I have also had prescribed medication which has caused similar problems. Many prescription medicines contain caffeine, sweetners and food colourings (azo dyes) which are not used so much elsewhere now.
I have to read the labels on everything I buy, to avoid problems. This issue has got much worse as I have got older. I still get caught out regularly because I forget to check, or succumb to the temptations of chocolate, or eat things just to be polite.
I hope some of you find these ideas helpful.