Obese teenagers are likely to earn 18 percent less as adults than teens of average weight, a new study finds.

The study was conducted by researchers from Linneas University and Lund University. For the study, the team compared extensive information from Sweden, the United Kingdom and the United States.

This included analyzing data  of145,193 Swedish-born brothers who enlisted in the Swedish National Service for mandatory military service between 1984 and 1997. Researchers gathered information from  military  personnel and certified psychologists about the soldiers' cognitive skills (such as memory, attention, logic and reasoning) and their non-cognitive skills (such as motivation, self-confidence, sociability and persistence), which can affect their productivity. Tax records were then used to gauge the annual earnings of this group of men, who were between 28 and 39 years in 2003. The Swedish results were further compared with data from the British National Child Development Study and the US National Longitudinal Survey of Youth, 1979.

Researchers found that obese teenage boys may grow up to earn 18 percent less in adulthood. Researchers noted that while the findings hold true for men who were already overweight or obese as teenagers, it wasn't the case for males who gain excessive weight only later in life.

"To put this figure into perspective, the estimated return to an additional year of schooling in Sweden is about six percent. The obesity penalty thus corresponds to almost three years of schooling, which is equivalent to a university bachelor's degree," the authors explained in a press statement.

Data from the United Kingdom and the United States showed similar readings. This clearly shows that obesity in adolescence plays a part in how much you earn later on in life. Researchers attribute these wage discrepancies to self image, bullying and discrimination from teachers and peers.

"Our results suggest that the rapid increase in childhood and adolescent obesity could have long-lasting effects on the economic growth and productivity of nations. We believe that the rationale for government intervention for these age groups is strong because children and adolescents are arguably less able to take future consequences of their actions into account," said the study authors. "These results reinforce the importance of policy combating early-life obesity in order to reduce healthcare expenditures as well as poverty and inequalities later in life."

Findings were published online in Springer's journal Demography.