It's tempting when you have a dip in energy, a mood swing, or any problem really, to want to revamp your diet as a first course of action. Food isn't always the problem though. How's your sleep lately? Your hormones? Your caffeination? Been around any sick people? Is work boring?
I definitely have days where I have less energy and can hardly keep my eyes open at work. I can't always pin it to a cause. I suspect that watching golf on television in a dark room would give anyone narcolepsy. Two nights ago I dozed off in a tall chair on fast wheels. As soon as I nodded, my weight shifted and the chair took off! WHOA! It tripped the ancient hominid falling-out-of-a-tree reflex. LOL But I don't think it had anything to do with what I ate or didn't eat. Some days I have the energy to be on my feet for 10 hours and walk for miles and other days I'm seriously compelled to hold still, rest, conserve energy. The trick is not to project any meaning onto either state. Being sleepy and resting more doesn't mean I'm lazy, hopeless, or eating wrong. Having enough energy to walk a half marathon and fidget all day doesn't mean that's my new baseline activity level.