After the age of 40, a bit of extra weight contributed to a more youthful look; a 4 point difference in BMI (equivalent to a 20 to 25 pound difference) apparently helped smooth out and softened wrinkles over their thinner twin.
According to Richard D. Hurt of the Mayo Clinic, the nicotine in cigarettes causes a narrowing of the blood vessels in one's skin, impeding blood, oxygen, and nutrient flow. This, along with chemicals from the nicotine, will cause the skin to sag and wrinkle prematurely.
Examiner.com by Tina Tuszynski , 12/27/09