Being obese is never good for one's health. But being obese at 20 can haunt you for a lifetime, says a study just presented in Stockholm.

Danish researchers sifted through health records for 362,000 conscripts tested for military service as far back as 1943 to find the nearly 2,000 obese ones.

Surveys of them later in life (at ages 35 and 46) and data on nearly 4,000 randomly selected young men from the conscript pool showed that being obese at 20 was associated with an 8-year decline in lifespan that became apparent in middle age.

Overall, a man who was obese at 20 was twice as likely to die at any given point in time as one who didn't have a weight problem early on.

In fact, being obese at age 20 carried a higher risk of death that persisted for as long as 60 years, the researchers said. Though, if we make it to 80, we're probably not going to complain if someone else lasts a few years longer.

In a statement, lead researcher Esther Zimmermann of the Institute of Preventive Medicine in Copenhagen, said it's not clear if being obese at age 20 by itself is the problem. It may be that early obesity raises the odds someone will be obese for a lifetime.

In the study, nearly three-quarters of obese 20-year-olds were still obese at subsequent exams. Only 4 percent of the randomly selected non-obese men became obese later on. [Copyright 2010 National Public Radio]