I saw a pretty interesting documentary last night.
Basically, they removed one gene from the DNA of a rat, and this caused the aging process to be half as fast. So for instance, it's the equivalent of an 80 year old looking and feeling like a 40 year old. Anyway, this gene basically plays a big role in insulin levels. Without it, insulin is much lower.
I guess insulin is also controlled by food intake. The more you eat, the more insulin is released. Thus, eating less food is extremely beneficial...
Also, they mentioned red wine. Red wine increased a mouse's life by 10-15%. However, for a human to get the same benefits, they must drink 10000 glasses a day... obviously, this would harm you in other ways... so it doesn't really work out.
A link I found: CBS NEWS