I'm a little embarrassed I've never thought about this before. When having it set to automatically give some percentage to body you will end up with the screen full of big berthas and when they die will fill the screen with energy shots, which will slow down the sim enormously. Of course you could set the corpses to release all their body mass in one shot, but that would look unrealistic. I prefer to let them decay slowly where other bots can pick up the particles, like they slowly feed from the nutritious water. So it's both more natural and better for performance to let some bots evolve the ability to convert energy to body.
