But yes, our work environment are full of dogmatic rules and preconceptions which are hard to break.
Recently I started doing more things in the morning hours, with the hope that I'd be more effective at those tasks (especially the more mentally taxing ones) earlier in the day than when I had been doing them previously, which was typically in the afternoon or evening.
Intuitively, this would lead to better productivity in the earlier half of the day at the cost of reducing it in the latter half. Instead, my afternoon and evening energy levels remained unchanged or even improved a bit, meaning that I now get more done with no apparent cost. This is of course welcome but it was quite unexpected, and suggests that some amount of the "tired" feeling is more a result of conditioning than energy expenditure.
The body can be affected by so many things, and it's different for people what affects them. What you eat in the morning, sunlight exposure and consistent bedtimes is what worked best for me. I get an afternoon slump no matter what I do, but that is usually remedied by some physical exercise or breathing exercises I've found, and the longer I go without taking naps, the more my natural rhythm gets used to not sleeping at that point. But I've had periods with extra stress where I just need to take naps, but that is just something I've accepted and enjoy now when it happens.