Men, there's more reason to be proud of your "Dad Bod."

A new book authored by Richard Bribiescas claims that "Dad Bod" acquired during fatherhood boosts health and attractiveness in men. Men who also gained weight during this period are also more likely to have a longer life compared to their "skinny" counterparts.

Bribiescas, the deputy provost of Yale University and also a professor of anthropology, associated his argument with the decreasing level of testosterone common in older men. He explained "one effect of lower testosterone levels is a loss of muscle mass and increases in fat mass. This change in body composition not only causes men to shop for more comfortable trousers but also facilitates increased survivorship and, hypothetically, a hormonal milieu that would more effectively promote and support paternal investment."

The steroid hormone Testosterone, which is produced by testes, governs male sexual characteristics. Low testosterone level is often associated with more fat and less muscle among aging individuals. One evidence that shows the correlation between testosterone and aging was a study of castrati or eunuchs. The testicles of these people were removed, and the study suggests that they can outlive non-castrate individuals by more than 20 years.

There is no precise ground for this argument. However, some possible mechanisms that may provide explanation include the increased immunity against infection and reduced risk of prostate cancer. However, low testosterone level is also associated with decreased mobility, poor cognitive function, lower energy levels, and a decline in sexual function.

Meanwhile, a Notre Dame study states that aging males with lower testosterone level are likely to have stronger relationships with their colleagues and families.

"Dad Bod" may be a factor for a longer life. However, a healthier lifestyle lengthens life for both fat and skinny individuals.