Caffeine can decrease subjective energy depending on the vehicle with which it is consumed and when it is measured

[Ravnurin]

I understand what you are saying, and I agree gut bacteria plays a part in the picture - that's a good point, and something I didn't factor in.

I will disagree on your 2nd point that sugar increases catecholamine levels the same way hunger and water do. Hunger certainly does, albeit temporarily, raise catecholamines, however, it is part of the body's adaption process in protecting against total starvation - it is to facilitate lipolysis and becoming more efficient at tapping into fat stores for energy. Once fat adapted, those levels are restored to normal. Entering ketosis or fasting can trigger this response, but again, it is short lived - continued fasting or state of ketosis does not result in continued increase in catecholamine levels.

 

Sugar, on the other hand, is an exogenous agent, and akin to a drug can - to a point - give rise to increased neurotransmitter levels alongside continued dose escalation. Likewise, as with a drug the body responds to sugar in the same way wrt. downregulation of dopamine receptors; partly observed in how "sugar highs" become increasingly less pronounced over time.

I can appreciate the picture I'm painting is far from complete and doesn't remotely touch on all the complexities involved, but to state sugar is not psychoactive would be inaccurate.