We may be vastly underestimating obesity’s toll.

As obesity rates have hit global epidemic proportions, researchers are finding new ways that excess body fat harms our health. This week, a new study adds another worry to the list: Being overweight or obese in adolescence seems to put people at a higher risk of dying from infectious diseases by middle age.

In a first-of-its-kind paper, published in the International Journal of Obesity, researchers from the Israel Defense Forces gathered data on 2.3 million people and found that even a few extra pounds early on in life was associated with an increased risk of death from infectious diseases — such as sepsis, pneumonia, and HIV — before the age of 60.

“There’s been an increase in both the US and Europe of infectious diseases deaths among young and middle age adults,” said lead study author Gilad Twig, a physician from the Israel Defense Forces and professor at Sheba Medical Center in Tel Aviv. In the US, for example, researchers have found a 0.5 percent annual increase in the rate of deaths attributed to common infectious diseases among middle-aged women over the past two decades. Now Twig and his colleagues think part of that trend may be explained by the rise in obesity.

For the study, the researchers drew from a data set of 2.3 million Israelis ages 17 to 19 who were screened for fitness before starting mandatory military service between 1967 and 2010. In these military health assessments, height and weight are measured along with vision, diabetes, asthma, and other health risks.

The researchers then linked this youth data with cause of death information from the Ministry of Health, focusing in particular on the relationship between body mass index (a measure of body fat calculated by dividing one’s Read More Here