Not necessarily. I feel way better when I work out in the morning without any food first. I think it's because my body doesn't have to spend any energy digesting food while exercising. This is true whether I'm doing a weightlifting session or a few hour trail run
I rolled the bones myself and it seemed like it worked, therefor X.
No, I rolled the bones myself and it seemed like it worked, therefor Y.
We would first have to define what we are even talking about by "energy" and "workout" to have any kind of real conversation.
The popular mind on this subject is also not even up to the point we sequenced the genome. What people think of as truth is mostly repeating things from the 1990s.I rolled the bones myself and it seemed like it worked.