>a hidden variable, such as excessive blood sugar Well we do know that eating a lot of sugar increases insulin production and insulin enlarges cells. I am not

>a hidden variable, such as excessive blood sugar Well we do know that eating a lot of sugar increases insulin production and insulin enlarges cells. I am not sure about the whole causation/correlation part of it, but for example with increased insulin production, fat cells become larger and their will be a greater likelihood of obesity even in skinny people. Moreover, I understand it is common for people with high insulin levels to have enlarged organs. It is an outrageous theory, but maybe the difference in the brain is simply cell size due to insulin since that might affect appearance but not function.