Lack of household work for modern women might be contributing to obesity, a new study has claimed.

According to researchers, since the 1960s, more women have taken desk jobs and cut back on physical activity like household chores.

In 1965, the average women spent nearly 26 hours per week on chores like cooking, cleaning and doing the dishes. Women today allot about half that time for chores, the study revealed.

"What we were trying to find is what has changed in our environment that has led to obesity," study leader Edward Archer, a researcher at the University of South Carolina, told the New York Daily News.

What changed, he said, is that more women went to work at sedentary jobs and fewer engaged in physical activity - like housework.

Obesity rates have been increasing steadily in past decades. In 2004, 32 percent of Americans were obese, compared to 13 percent in the 1960s, according to research from the Johns Hopkins Bloomberg School of Public Health.

For Archer`s study, researchers looked at the time and amount of energy women expended on "household management" over a 45-year span.

Non-working women spent 33.1 hours per week on housework in the 1960s, compared to 16.5 hours in 2010. Working women spent 17.1 hours on housework in the 1960s, compared to 10.4 in 2010.

By 2010, women were devoting 25 percent more time to "screen-based media use" - watching TV or on the computer.

The study is published in the science journal PLOS One.