I've adopted a mostly paleo type of diet for the last 6 months now, and I've noticed a difference in my health, which in turn has affected my mood for the better. I do still have dairy, but I buy organic whole milk and even then, I get small quantities and don't have it every day. The biggest thing I've cut out is processed foods, so anything out of a package with ingredients I can't even pronounce are out. Also, I take a good quality probiotic to help with digestion issues.
Has your family been screened for MTHFR mutation? I ask because apparently it is incredibly common among people in the autism community. I have it, and because of it, I have problems processing regular folic acid and I'm chronically low in B12 and folate... so I eat lots of greens and take vitamins in the pure forms (so I take folinic acid and folate as opposed to the synthetic folic acid, and methylcobalamin (pure, active form of B12) as opposed to cyanicobalamin (synthetic B12)). When I am eating well and taking the right kind of vitamins, my mood is awesome and I have more energy and my sensory issues affect me less.
ETA: The MTHFR mutation goes beyond just the folic acid processing issues... it's like a domino effect and causes malabsorption for other vitamins when things get out of whack and it affects the methylation process of the body (the way the body detoxes itself), so as a result, people with it can have a harder time getting better from being sick and tend to be extra sensitive to things in their diet or what they put on their body (like lotions, shampoos, etc).
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Your Aspie score: 136 of 200
Your neurotypical (non-autistic) score: 77 of 200
You are very likely an Aspie