05/08/2012 04:10 pm ET Updated Jul 08, 2012

Fifty Shades of Grey : The Nutrition Footnotes

My writer friend Catherine and I were discussing books. "I had to get a copy of Fifty Shades of Grey," she reported. "Everyone is going on and on about it but I don't see what all the fuss is about."

I had not heard about the fuss but once she started talking I quickly realized the only way to avoid looking like a complete yahoo was to not mention the book I was currently reading on a cappella singing. Instead, the next time I was at my local bookstore I asked the very nice manager about the book. He stammered that it was a number one bestseller and handed me a copy without meeting my eyes.

In case you are one of the three people left who has not heard about Fifty Shades, it is cleverly written erotica about an innocent young college graduate and a troubled billionaire. (Guess which one is the woman?) They have inhuman amounts of sex in varied and sundry ways. The billionaire, named Grey, has control issues and the couple spends much of the book arguing about what he gets to control followed by a lot of graphically described sex.

What does this have to do with nutrition? A lot. People obviously enjoy reading about having sex but if they actually want to be having more sex, being in good nutrition shape is critical. You might be surprised at how much, as a nutritionist, I hear about people's sex lives. Just today I had a conversation with a client about improving his diet so he could improve erectile functioning. Another woman complained recently that she had not had sex with her husband for over a decade. Still another person came to see me ostensibly for fatigue but what she really wanted to talk about was low sex drive. In a nutshell, when people do not feel or eat well, sex drive is one of the first things to go.

In my experience, plenty of people do not have enough stamina for plain old sex, let alone the exhausting gyrations depicted in the erotic bestseller. The Kinsey Institute concurs. They report approximately one-third of married couples, after age 40, are not having sex at all.

Undoubtedly, there are many emotional factors and medical problems to blame. Female sexual functioning, in particular, is shockingly poorly understood, though not from lack of trying. Apparently, we are complex. While scientists are busy chasing down disease and psychological causes, the dietary factors are barely noted.

In Fifty Shades, one of the areas Grey wants to control is what the heroine in the story eats. While she is comfortable with being tied up and whacked, she will not let him direct her diet. I am thinking she should hand him back his tie and agree to let him pick her food -- because her diet of bagels and cosmopolitans will not give her the stamina she is going to need to get through two more books.

The young heroine is in her early 20s, and does not yet see the link between what she chooses to eat and her sexual stamina and functioning; but her partner, who is only a handful of years older, already knows. The three cups of coffee and doughnut you use to get through a busy morning may not serve you so well later in the bedroom.

While it is difficult in studies to draw a direct connection between what you eat for breakfast and how you function sexually later that night, it is clear that long-term poor eating, especially when it leads to obesity, is associated with sexual malfunctioning. This revelation is not exciting. Most people would probably prefer more studies such as the small German study that found high levels of vitamin C were associated with increased intercourse frequency. These single-nutrient sexual fixer-uppers are appealing, but cannot work consistently when used alone. The reason the National Institutes of Health budget will not include a search for aphrodisiacs anytime soon is because good sexual health is related to good general health, not the number of oysters you consume.

The nutritional footnotes to 50 Shades are if you want to try some of this at home, eat your fruits and vegetables, cut down on the junk food and drop those extra 20 pounds. No billionaire required.