Something I've been wondering is to what extent we're gut-efficiency-limited rather than calorie-limited. There's plenty of research showing that brain develop

Something I've been wondering is to what extent we're gut-efficiency-limited rather than calorie-limited. There's plenty of research showing that brain development and food preparation went hand in hand (cooking allows humans to liberate more calories from food with the same sized gut, allowing us both to be pretty mobile and have more energy available to run our large and energy-hungry brains). If you look at the way guts are built, clearly nature/evolution is trying to pack as much intestine as possible into a limited space. Certainly increasing calorie availability beyond a certain point isn't a good thing - our brains can't burn more than a certain amount, and most of us, Michael Phelps excepted, don't like making our bodies do the same - but I wonder to what extent our design-constraints put limits on our ability to absorb non-calorie nutrients. On the one hand you have a supplement industry who will say anything to make a buck, and are infected with pseudoscience and woo, but on the other, the standard med-sci advice of "just eat a balance diet, it's impossible to improve on that" seems kind of glib and baseless.