> optimizing diet and rigorous exercise comes at some cost in the form of time spent in your precious youth. so you sacrifice youthtime for a chance at a longer better old age. each hour of exercise does not make you live an hour longer, so you are net negative from the get-go.
Pretty much all science on exercise's impact on both physical and health can be loosely summarized by "doing anything, anything at all is likely to have significant short and long term benefits". Similarly, nutrition can be summarised as "try eat a balanced diet, but at the very least just avoid hyper UPF, and don't eat red meat every day". You might decide that's worth it, but "walk your kids/dog/partner/self twice a day and only eat red meat on the weekends" is probably enough to make a significant impact for a very significant number of people.
Pretty much all science on exercise's impact on both physical and health can be loosely summarized by "doing anything, anything at all is likely to have significant short and long term benefits". Similarly, nutrition can be summarised as "try eat a balanced diet, but at the very least just avoid hyper UPF, and don't eat red meat every day". You might decide that's worth it, but "walk your kids/dog/partner/self twice a day and only eat red meat on the weekends" is probably enough to make a significant impact for a very significant number of people.