That's men for you: There she is in the supermarket, slim as a greyhound, choosing her low-calorie meal for the evening. Before she has her "dinner" she will go to the gym just to ensure that she stays nice and slim.
You, however, may prefer your women not to be all muscle and bone but don't worry - all you have to do, the latest research suggests, is to marry her.
It appears that marriage makes women gain weight. Is this because marriage makes them content and happy? I would like to think so but researchers have a way of spoiling the fun.
A British obesity expert, Dr David Haslam, writing recently in the Lancet, said living with a man means the woman eats bigger meals than when she was single.
Men need more energy and, therefore, need more food, says Dr Haslam, so out go those little meals for one and in come the bigger portions and perhaps a bottle of wine will become part of the evening meal. The woman will gradually drop her trips to the gym in favour of a night in.
But I'm afraid bigger meals are not the only thing your once trim babe is going to share with you. According to research by the University of Nottingham, married couples are also more likely to share high blood pressure and excessive levels of cholesterol. Some of this, of course, could be related to those bigger meals. It could also be related to other lifestyle factors - both may be smokers, couch potatoes or may live in a stressful atmosphere.
The findings even apply to depression. If your partner suffers from depression, your chances of suffering from it are 70 per cent higher than normal. Researchers speculated that this might be because both partners are living in the same depressing social circumstances. They also speculated that people tending to be depressed might gravitate towards other people who also tend to be depressed.
It's all a bit grim. And yet death rates among married people are lower than death rates among their unmarried counterparts. Married men and women in any age group are less likely to die than those who are single. Perhaps this is because they have someone to give them emotional support. The married person, for example, has a spouse to nag him or her into going to the doctor if something appears to be wrong.
Typically, it is the man who is nagged by the woman into going to see the doctor. From a male perspective, women seem ready to skip down to the doctor's surgery at the drop of a hat. A man may decide to give himself, oh, say, a year to see if he can get better on his own before bothering the GP. So the nagging of one spouse by the other is probably helping to keep both of them alive. But if the nagging drives you to divorce, your chances of dying early will increase substantially.
Men and, I suspect, women who have been divorced drink more heavily than their married counterparts. But if they are sensible, the divorcees will return to buying those little meals for one and heading off to the gym every night. Then they will become trim and slim again and can snap up a new partner and start over. And this time they could trade in the sofa for a gym membership for two, ban those big meals and live healthy lives all round. Mind you, I think I would rather be overweight and lazy and happy. But don't mind me. I am just a man.
Padraig O'Morain is a journalist and counsellor accredited by the Irish Association for Counselling and Psychotherapy.