I eat a small amount each day of the Japanese food natto which contains high amounts of vitamin K2, and the enzyme nattokinase, which is derived from natto.
I've never experienced any decrease in energy. I eat natto specifically for the K2 in place of a K2 supplement and eat a specific amount of the natto to get a certain amount of K2. By default, I also take in nattokinase from the natto.