If one partner has obesity, the other is likely to head that way, too. Getting married or moving in with a partner can be risky, it seems. Some studies have shown progressive weight gain in both women and men in the years after they tie the knot.
The opposite, of course, could also work. If our partner is keen on exercise and a healthy eater, we may adapt our own habits to be more similar, as we merge our personal "food systems".
In general, though, marriage is good for us. Married people tend to have better heart health and mental health, and live longer than unmarried people. If you're a man, the benefits of marriage are particularly strong. Research that showed the opposite to be true for women — that women are happier and healthier when single — seems to have been superseded; marriage seems to be good for women, too. Although so is being single.
There hasn't been much research looking at same-sex marriages, but an Australian study last year found both heterosexual and gay and lesbian people are better off in terms of health when married than when unmarried.
Bearing in mind, then, the influence we do and can have as romantic partners, here are some suggestions for loving things you can do for and with your partner to help both of you gain greater health.
Cook and eat together
Over time, perhaps as we settle into being a couple, we may end up eating worse. A 2018 Australian study found couples tended to eat more fast food and fewer fruits and vegetables as marriage progresses. A way to avoid this could be making time regularly to cook a meal together, and making time to sit down and eat that meal together, too.
Ideally, this would be without devices or screens.
Move together
There's some evidence showing single people exercise more frequently than married people. But you can buck that trend by making your partner your exercise buddy. Go for walks or runs together; plan your gym visits together and track your progress together, too. If you've got kids, get active as a family for even more benefits.
Share your stresses
One of the ways married people enjoy better health is with lower stress levels. It might be that sharing the things that are stressing us out with our partners helps us, lowering stress hormones and inflammation. So take advantage of that listening ear at home, and make sure you regularly offer yours, too.
Have a favourites night
I'm no relationship expert, but I reckon one key to a good one is to respect each other's differences. No couple, no matter how close, is going to love eating the exact same food all the time. We all have different tastes and preferences. It's nice to adapt to this — both of you — and make sure you incorporate each other's favourites into your regular eating routines. If bangers and mash is your partner's go-to comfort food and yours is chicken Caesar salad, incorporate these into one night every now and then where you both get to eat exactly what you want. If you have to go out to get it, that's okay. Occasional indulgences are part of a healthy relationship with food.
Don't be matchy-matchy
It's obvious, but easy to forget: women (in general) need less food than men. The eating risk women face when partnering up with a man is portion creep; the tendency to serve and eat similar amounts of food and to match up the portions. That could be part of the reason women tend to gradually gain weight after marriage. Just being mindful of portions can help avoid this.
"Sesame seeds are high in calcium"
We often see claims like this on foods. "Spinach is high in iron" is another one. They come about because things like sesame seeds contain minerals like calcium in relatively high proportion.
However, that doesn't mean they're a useful way to get those minerals. Nothing against sesame seeds – they're delicious - but do you know the volume of seeds you'd need to eat to get the same calcium you'd get from a glass of milk? By my calculation it's about three cups. Best to enjoy sesame seeds in moderation for their crunch and flavour (tahini's pretty good, too) and look to dairy for calcium.
* Niki Bezzant is a food and nutrition writer and speaker. Follow her on Facebook or Instagram @nikibezzant