On Wednesday I wrote about how women are way behind men in putting money away for retirement. Even though women are equally likely to contribute some amount to an individual retirement account, they lag in overall savings. A study from the Employee Benefit Research Institute showed that women make smaller contributions, on average, when compared to men, but researchers couldn't fully explain why.

Many readers commenting on the article on Twitter agreed with one of the possible explanations I posed in the article -- that women may have a harder time making equally large contributions because they still make a lot less money, on average, than men do.

But some readers offered up another culprit for why women are trailing behind men in retirement savings that surprised me a little: shoes. One reader blamed both pay disparity and footwear, commenting that women have "typically had less to save and more shoes to buy." Another blamed the lesser savings on lifestyle differences, noting that women have to deal with "dry cleaning, hair, clothes and makeup," while men wear khakis, a white shirt and a blue blazer every day.

Surely, many of these comments were sarcastic, but it still made me wonder: Are women really that much more likely than men to spend their money on shoes? (I also couldn't help thinking of that episode of "Sex and the City" where Carrie Bradshaw says she can't afford to buy her apartment because she spent all of her money on Manolo Blahniks.)

Apparently, there is some truth to the idea, according to the Bureau of Labor Statistics.

Single women spend an average $1,039 a year on apparel and services, including an average $160 a year on shoes alone, according to BLS. Single men spend an average $817 a year on apparel and services, including $143 spent each year on shoes.  So, the data suggests, women spend an average of $17 more per year on shoes.

Women outspend men much more dramatically -- $534 a year compared with $205 a year -- when it comes to personal care and services, a category that includes hair cuts. Interestingly enough, the tables are turned when it comes to alcohol -- on which single men spend an average of $508 a year compared with the average $234 a year spent by single women.

So, there is a sizable difference in the amounts that men and women spend on things like clothing and shoes. But is that really the reason why men have such a lead in saving toward retirement?

Probably not. The savings gap likely has a lot less to do with women's shopping habits and a lot more to do with the fact that women still earn 77 cents for every dollar that men earn.