You achieve a grill garden (GG) when a significant portion of your food ends up staying in your front teeth. All ages can achieve a GG, but the receding gums of the over 50 crowd are both more susceptible and less embarrassed by it.
(After lunch)
SIS: What's up with dad's teeth?
BRO: He's just sporting his grill garden. His Silver Singles profile pics are more impressive. Maybe he's trying to attract some vegetarian women or maybe salad just sticks in his teeth more.