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Your mom (or grandma) is still alive at 95, and she was no health nut.

Family studies have indicated that genetic factors account for around 20 to 30 percent of the variation in the adult lifespan. One gene that scientists have their eye on is APOB, a cholesterol transporter that helps carry "bad cholesterol" in the blood. You might have it!

And if you suspect you don’t, focus on the 70 percent, some of which is definitely within your control. Two words: Eat nuts!