All of this reminds me that I am looking for dextrose tablets.  Many years ago they were common.  Individually wrapped 1x1x1/4" tablets.  They have a slight orange flavor.
I still have one or two and have not found anything that quickly remedies that shakey, gonna crash any minute now, feeling when I am over-stressed. Instant energy, but of course it does not last like a good meal.  However I think they have saved me many times as I find I am able to continue my task without the danger associated with the "shakies".  
Probably not the best thing health wise, but they sure work.  Anybody know where I can get them?   
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...........From Nomad.........Been "on the road" since '97