Sex and body weight — these two topics can be difficult to discuss on their own, let alone together. But a new study, which demonstrates a correlation between weight and both sexual behavior and sexual health outcomes, demands such a discussion if its troubling findings are to be fully explained and addressed.
The study, published on the Web site of the journal BMJ, looked at over 12,000 men and women in France between the ages of 18 and 69. To try to get a normal cross-section of the population, potential participants were contacted randomly using both the phone book and cell phone records. Those who agreed to participate were given an oral questionnaire; all information obtained for the study, including participants’ weight, was self-reported. Based on reported weight and height, 9% of both men and women in the study were obese (indicated by a body-mass index, or BMI, of 30 or higher), and 35% of men and 21% of women were overweight (with a BMI of 25–29). Obese participants were found on average to be older, less educated, and more likely to have a chronic medical condition such as diabetes, cardiovascular disease, or depression than the other participants. For this reason, the researchers controlled for age, education level, chronic diseases, and other characteristics when looking at how weight was connected to sexual outcomes.
The researchers found that obese women were 30% less likely than other women to have had a sexual partner in the last year; however, obese women ages 18–29 were three times as likely as normal-weight women to have met a sexual partner on the Internet. After further controlling for lifetime number of sexual partners and coupled status, among women under age 30, those who were obese were four times as likely as normal-weight women to have had an unintended pregnancy at some point or an abortion in the last five years. Obese women were less likely to have seen a doctor for contraception in the last year and a whopping 70% less likely to have used oral contraception (“the pill”). While there may be valid medical reasons for obese women not to be on the pill (some people think it is less effective in obese women or that it increases the risk of dangerous blood clots), another result from the study indicates that avoiding risk is not what motivates the different contraceptive choices seen in heavier women: The higher their BMI, the less likely women under age 30 were to have used condoms and the more likely they were to have used the unreliable method of withdrawal for birth control. Obese women were eight times as likely as normal-weight women to have used withdrawal.
Among men, those who were obese or overweight were no less likely to have had a sexual partner in the last year than normal-weight men, but they were less likely to have had more than one partner (obese men were 70% less likely). Both overweight and obese men were more likely than normal-weight men to have had erectile dysfunction often in the last year, with overweight men 2.69 times more likely and obese men 2.58 times more likely. Obese men ages 30–49 who had had more than one sexual partner in the last year were less likely than normal-weight men to have used condoms, and obese men under age 30 were more likely than normal-weight men to have caught a sexually transmitted disease in the last five years.
A higher rate of erectile dysfunction in overweight and obese men can probably be explained physiologically fairly easily. But what are the likely causes of the weight-related differences in sexual behavior found in this study? Given the social stigma associated with a higher body weight, it is perhaps understandable that fewer obese people would have sexual partners, but why would obesity make someone less likely to use contraception or protection from sexually transmitted diseases? Do you have any insight — either from your own experience or through someone you know — into how being overweight or obese might create (or, possibly, be the result of) a mind-set that leads to such behavioral differences? What can medical professionals, or overweight and obese people themselves, do to improve their sexual habits and outcomes? Leave a comment below!