Where OCD is...I'd wonder about impaired glucose utilization, and poor
inositol levels. Inositol really improves glucose use in the brain.

But also, sugar jolts, cause sudden rises in insulin, which then has a negative
impact on EFA metabolism. This is why high sugar loads, lead to more hunger.
And constant sugar consumption can impair the whole EFA sequence. Isolated intakes less so.

Also the "crash" when the sugar is removed suddenly from the blood, leads to all sorts of
negative feelings. Sugar itself doesn't last long in the body after absorption.
That is sugar combined with low fiber intake...cake, icing, cookies, candies.
Some sweet following a large meal can turn off hunger..that is why we have desserts (but they are diluted with the full meal that way).. Also sweets before bedtime, release some serotonin and that helps some people sleep. But I have found at least for me, that high glycemic carbs, or candy actually stimulate hunger, an hour or so down the road. If I keep it very low, like 10 M & M's, or a cup of cocoa (70cal), it is less of an issue--I try not to go over 100 cal doing this). As we age, we old folks feel low blood sugar more acutely than kids do.
I find after a long hard day, driving home in the dark, tired, that those 10 M&M's (the new dark variety) wake me up a bit and improve my driving skills.
Any more and it is awful, and none, is pretty grim too! So now you know my "secret"?

Sugars in fruits are hidden in the fiber, so they have a longer onset, and
less of a up/down impact. So drinking juice is more problematic than eating an orange or apple.