Jonathan Mendes promised his children last year that he had run his last marathon– but he couldn't stay away.

Last Sunday, the week of his 95th birthday, he was set to run the New York City Marathon.

How does the ex-Marine stays so young?

He eats lots of fish, vegetables and fruits, he told USA Today.

He used to run regularly in Central Park until his doctor told him his joints were taking a beating. Now, he walks two miles before breakfast and about two miles after. Twice a week, he works with a personal trainer at the gym in his building.

(Watch the video below)