I've heard white corn syrup was the same a nutri-cal. I sounds like it could be symptoms of hypoglycemia, usually they aren't hungry when they have an attack, and won't eat, which would cure the hypoglycemia, so that's why corn syrup is rubbed on the roof of their mouth for fastest results. This usually brings back their appetite, so it's good to have food available for this. Many people recommend free feeding so they never get too hungry, they can wear out the calorie reserves so fast through activity or stress. Here's a video of what an attack look like.
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