There's a lot of buzz going round the net about low carbs = low energy. If that's your personal experience I can't argue with it but it certainly isn't mine. Instead of slumping after lunch and dinner as before, I'm energetic all day. I am not super low carb and I'm not sure I'm in ketosis but I try to avoid all obvious carbs, with the exception of veggies and the occasional serving of rice. There is a lot of info on this forum about the science of low carb which might be interesting for you.