children, adolescents, and young adults (under approx 21) should be advised against starting CR. Physical growth may be impaired by calorie restriction, as observed in lab animals. In addition, mental development and physical changes to the brain take place in late adolescence and early adulthood that could be negatively affected by calorie restriction. For this group, the best advice is to follow a normal (non-CR) diet until reaching early twenties.
However, according to this, brain development continues "well into our 20s" (i.e. beyond approx 21). I am wondering if starting CR in one's early or mid 20s would impair brain development. I recall reading that CR can also slow brain deterioration, though, so it might be the case that starting CR in one's early or mid 20s would still be a net positive for brain functioning in the long term.
Any relevant insights would be appreciated.