I switched to drinking tea instead of coffee, all day long. For the most part, I've noticed that I don't experience the afternoon slump as much. On the occasions that I do, a half cup of coffee usually overcomes it.
I've also experimented with intermittent fasting, only eating between noon and 8pm. That also, for me, helped eliminate the slump.
I've also experimented with intermittent fasting, only eating between noon and 8pm. That also, for me, helped eliminate the slump.