Would luvox and paxil (paroxetine) be the worst ssri's for potentially slowing down ones metabolism?

It depends.: I am not sure what you mean by slowing metabolism. Luvox is more specifically used for obsessive compulsive behavior, and not as an antidepressant even if it is an ssri. Paxil (paroxetine) had been used for ocd but also a good antidepressant. The relief of anxiety associated with those conditions could be interpreted as slowing the metabolism.

Wrong question: Ssris don't change metabolism. All ssris increase serotonin throughout the body. Most of our serotonin is in our gut and our platelets. Increasing serotonin increases our appetite and decreases our sense of fullness. Most of us eat until we are full and don't pay attention to how much we are eating, and if we have less fullness we eat more. Be mindful of how much you put in your mouth.