That's men for you: Padraig O'Morain's guide to men's health
Is your ideal partner, the one you fantasise about spending the rest of your life with, as slim as a greyhound?
If so, the bad news is that if you want to attract this gorgeous skinny creature, you're going to have to get skinny yourself.
People get together for reasons which are not apparent to them at the time. For instance, we are often attracted to people who are the opposite to us in our personalities and even in our backgrounds. As the traditional phrase puts it, "opposites attract".
But the most recently discovered source of mutual attraction turns out to be body fat.
A study of 42 couples in Aberdeen found that people tend to be attracted to others who have the same amount of fat on them.
So if you are thin, you are likely to "end up" - if that's not too pessimistic a phrase to use about marriage - with somebody who's thin.
If you're plump, you are likely to walk up the aisle with another plump person.
The researchers who did this study point out that it wasn't always like that. Back when people used to get married in their early 20s, it was still too early for either to know if the other would put on weight. Nowadays, we put off marriage and having children to a much later time, which gives us the opportunity to add on the pounds.
Therefore, we are now more likely to know who's our match when it comes to body mass.
This probably all has something to do with conformity. We like to think that we are mad romantics who will follow love wherever we find it but it's not like that.
However non-conformist we may believe ourselves to be, we will almost certainly marry into our own social class and our spouse will have a broadly equivalent income.
So, it is really not all that surprising that we are also attracted to people who look similar to us in terms of weight.
Some commentators have unkindly suggested that this could contribute to the increase in obesity as large persons marry each other and give birth to children who are genetically disposed to piling on the weight.
That sounds a bit alarmist to me. However, I have seen the theory about like attracting like borne out at a holiday apartment where the food was "free" in the sense that you didn't have to pay anything extra for what you ate during your stay.
There I saw entire families of incredibly large people eating all they could get.
Sometimes you saw an obese person with a thinnish person but more often everybody in the family was obese and they seemed to float as they carefully balanced their overloaded trays between serving counter and table.
What this research suggests is that the couples in these families didn't get obese because they were married and comfortable. They got married because they were obese.
Does that mean they have no incentive to change?
One of the more interesting findings in research on couples is that if one of them decides to behave in a more healthy way then there is a good chance the other will do the same.
In our more cynical moments we might complain that our spouses have driven us to drink but the research shows that our spouse may very well drive us off the drink by cutting down or giving it by herself.
This copycat effect is particularly strong for drinking and smoking. We influence each other more than we think.
And what this means of course is that if you want your spouse to behave in a more healthy way - by losing weight for example - your best chance of getting her to do so is to adopt a healthy diet yourself.
So we're back to where we started: be the way you want the other person to be.
Meanwhile, if you're single, do you want a glimpse of the future? Want to know what your spouse will look like? Spend a little time in front of the mirror. He will look a lot like what you see there.
Padraig O'Morain is a counsellor and his blog is at www.justlikeaman. blogspot.com