I grew up on absolute junk food and plenty of conventional red meat. When first tried to apply for my passport at age 24 they told me to come back with an adult because children under the age of 14 weren't allowed to apply for passports on their own. At 30 without a beard I would get mistaken for a high school student or if lucky a college undergrad.
Better counterpoint: my brother with hemachromatosis (and a smoker) looks just as young for his age as I do. And he subsists on a diet of oreos and cocacola.