The 2:19 50-year old world record was set by someone who was a 13:32 5K runner when he was younger (when the 5K world record was 13:31). A former world class runner is the profile of someone who should be the 50-year old world record holder (not someone who was a hobby jogger for years who improves every year in his 40s). There's only one explanation for this profile and it's not diet.