What does gut got to do with it?
The proportions of our bodies are a product of millions of years of evolution, including our stomachs! Our ancestor Homo erectus evolved a narrower ribcage and pelvis, shorter large intestines, and longer small intestines. This made the early human gut smaller and it decreased the time it took to digest food! The shorter gut allows for more energy to be diverted from the intestines to other important organs of the body, such as the brain.