I usually get very tired right after lunch so I started taking a short "power nap" of about 15 minutes before I get back to work. I do this in my car. I find a shady spot to park, roll the windows down a bit, set a timer on my iPhone, recline my seat, and close my eyes for 15 minutes. It has worked wonders for me. I have a new burst of energy in the afternoon and I don't have to rely on caffeine to make it through. Give it a try and see how it works for you.
What do you think?