Hopefully, everyone reading this right now has experienced at least one happy relationship in their life. It might have been a short fling, or it could be a long-term deal that you're still very content with today. Either way, you'll know what it's like to get totally caught up with someone else.

But, for all the good times you spend with that person, there's always one niggling side effect that you wish you could have avoided. You see, after all those dinner dates, the cozy Saturday nights spent with a takeaway pizza, and the lovingly-gifted boxes of chocolate, the relationship might have grown substantially - but so did your waistline.

And, while it's been easy to blame someone else for us getting fat all this time, scientists have finally confirmed that - actually - weight-gain in a relationship is a totally legitimate thing.

A new study conducted by the University of Queensland in Australia collected a decade's worth of data from more than 15,000 people and analyzed the amount of weight that individuals gained (or didn't) while being in a happy relationship.

What they discovered was that people who were part of a couple weighed, on average, 13 pounds more than their single counterparts, and gained an average of four pounds each year.

There are a number of speculative reasons for this difference, but the obvious ones would be the aforementioned indulgent lifestyle people often engage in when they're dating someone and, of course, the fact that folks don't tend to worry about their figure so much if they know that their partner would be happy with them even if they did gain a little weight here and there.

However, it's not all bad news for the loved-up couples out there.

The extensive study also discovered that, compared to single people, those in relationships tended to have generally healthier habits overall. They smoked less often, consumed less fast food, and were more likely to eat fruits and vegetables on a regular basis.

Plus, it's been proven before that happiness is linked to better health and a longer lifespan. Of course, this isn't to say that you can't be single and happy - of course you can - it just shows that those in relationships often have a better support system in place for when something bad does go down.

It also happens that happiness is also linked to body mass.

"Satisfaction is positively associated with weight gain," said Andrea Meltzer, the head researcher of a similar survey conducted by the Southern Methodist University in Dallas. "Spouses who are more satisfied tend to gain more weight, and spouses who are less satisfied tend to gain less weight."

So, if you have put on a little extra while being with your significant other, don't worry - it's just a sign that you're comfortable together. And, if you're currently single and feeling sorry for yourself, just remember that at least you have this as a one-up on all those loved-up couples

Hopefully, everyone reading this right now has experienced at least one happy relationship in their life. It might have been a short fling, or it could be a long-term deal that you're still very content with today. Either way, you'll know what it's like to get totally caught up with someone else.

But, for all the good times you spend with that person, there's always one niggling side effect that you wish you could have avoided. You see, after all those dinner dates, the cozy Saturday nights spent with a takeaway pizza, and the lovingly-gifted boxes of chocolate, the relationship might have grown substantially - but so did your waistline.

And, while it's been easy to blame someone else for us getting fat all this time, scientists have finally confirmed that - actually - weight-gain in a relationship is a totally legitimate thing.

A new study conducted by the University of Queensland in Australia collected a decade's worth of data from more than 15,000 people and analyzed the amount of weight that individuals gained (or didn't) while being in a happy relationship.

What they discovered was that people who were part of a couple weighed, on average, 13 pounds more than their single counterparts, and gained an average of four pounds each year.

There are a number of speculative reasons for this difference, but the obvious ones would be the aforementioned indulgent lifestyle people often engage in when they're dating someone and, of course, the fact that folks don't tend to worry about their figure so much if they know that their partner would be happy with them even if they did gain a little weight here and there.

However, it's not all bad news for the loved-up couples out there.

The extensive study also discovered that, compared to single people, those in relationships tended to have generally healthier habits overall. They smoked less often, consumed less fast food, and were more likely to eat fruits and vegetables on a regular basis.

Plus, it's been proven before that happiness is linked to better health and a longer lifespan. Of course, this isn't to say that you can't be single and happy - of course you can - it just shows that those in relationships often have a better support system in place for when something bad does go down.

It also happens that happiness is also linked to body mass.

"Satisfaction is positively associated with weight gain," said Andrea Meltzer, the head researcher of a similar survey conducted by the Southern Methodist University in Dallas. "Spouses who are more satisfied tend to gain more weight, and spouses who are less satisfied tend to gain less weight."

So, if you have put on a little extra while being with your significant other, don't worry - it's just a sign that you're comfortable together. And, if you're currently single and feeling sorry for yourself, just remember that at least you have this as a one-up on all those loved-up couples