When men point this study out to their wives:
Forty-five years later, in 2010, things had changed dramatically. By then, the time-use diaries showed, women were spending an average of 13.3 hours per week on housework.
More striking, the diary entries showed, women at home were now spending far more hours sitting in front of a screen. In 1965, women typically had spent about eight hours a week sitting and watching television. (Home computers weren’t invented yet.)
By 2010, those hours had more than doubled, to 16.5 hours per week. In essence, women had exchanged time spent in active pursuits, like vacuuming, for time spent being sedentary.
In the process, they had also greatly reduced the number of calories that they typically expended during their hours at home. According to the authors’ calculations, American women not employed outside the home were burning about 360 fewer calories every day in 2010 than they had in 1965, with working women burning about 132 fewer calories at home each day in 2010 than in 1965.
“Those are large reductions in energy expenditure,” Dr. Archer said, and would result, over the years, in significant weight gain without reductions in caloric intake.