I want to make a point that I think has been missed on this topic, our BPs are not in the wild. Observations on what they do in the wild are a great (because you definitely need a baseline), but observing what happens in captivity, the environment we care about in this situation is more useful. For the most part, our animals are not fending off parasites and predators, they expend very little energy finding food, and have the ultimate in climate control. Their growth rates and metabolic demands are probably rather different in captivity than they are in the wild, so it is important to look at trends of snakes in captivity*.
*I apologize for this incomplete chain of thought, I was thinking about experiences I've had with american mustangs (yes I know that snakes are not horses or mammals). When you take a pregnant mare or a weanling into captivity, and raise the baby in the same environment as 'regular' horses, they tend to grow MUCH bigger (we had a 16 hand foal out of a 14 hand mare for example). They also tend to get obese readily, probably because they have an evolved genetic tendency toward storing calories efficiently from centuries of living on comparatively poor fodder. Hopefully someone gets where I was going with this line of contemplation, because I lost track of my thought and got distracted thinking about lunch, sorry.