Well thats what the article says, though not twice as long but 4 years longer on average
(Sorry that wasnt in the article I posted, was in
http://www.adamsmith.org/blog/health...-the-nhs-money that one.)
On average, healthy people lived 84 years. Smokers lived about 77 years and obese people lived about 80 years. Smokers and obese people tended to have more heart disease than the healthy people.