I don’t know about foods that slows the aging process but there are research that shows that eating less… fasting, intermittent fasting does work to increase longevity.
The following video explains a bit of how it works and there are lots of other related videos and research online about the benefits of fasting
Fasting & Telomeres - Study
From the journal PLoS One, researchers used young mice - just three months old - and reduced their caloric intake by 40% before observing them until the end of their life cycle.
The researchers found that a calorie-restricted diet lowered the telomere shortening rate when compared to mice fed a normal diet, which led to a 20% increase in lifespan.
More specifically, they found that when mice are fed half their normal number of calories, they survive to either an extended lifespan of 32 to 45 months or - better yet - a maximal lifespan of 40 to 53 months.