The assumption is your environment is pretty similar to everyone else's environment, which means you don't die of hunger or get boiled in acid. But you raise a

The assumption is your environment is pretty similar to everyone else's environment, which means you don't die of hunger or get boiled in acid. But you raise a very important point, and you're right: as far as I'm aware, latest evidence says that being malnourished as a child does significantly impact intelligence as it does height (stunting). Though I believe the last piece of work I read on it claimed the effect was smaller than previously believed. That was ~2 years ago.