Does this relationship make me look fat?

"Kat, I need to come over right away. You home?"

"Yeah," I said to Mia, alarmed by the tone of her voice on the phone. "Are you OK?"

"Um, I, um, I'll see you in a few minutes."

I was worried, expecting her to show up in tears with bags under her eyes. Instead, she looked great in that feminine full-faced I'm-in-love way.

"What's up?"

"I need to use your scale."

"What?"

"Mine's broken."

"That's it? You came all the way over to my house to use my scale?"

She didn't answer, but I'm not even sure she heard me. She was already in my bathroom.

There was a bit of a commotion, and then she spoke. "Crap!"

"What is going on in there?" I asked her, half confused and half freaking that The Kid had left the bathroom a mess.

"I gained five pounds!" emerging from the bathroom looking slightly disheveled and clearly distressed.

"Oh for goodness sake, Mia. Everyone's gained five pounds — even me. We're post-holiday, remember?"

"No, no, no, it's not just that. Rex and I have been, well, we're struggling."

“I’m sorry, honey. Sean and I have been, too,” I said quietly in sisterly unity. Not only do women get their periods in synch, but sometimes it spills over into their love life, too. “But that’s not why we’ve both porked out.”

"Of course it is!'

"What do you mean?"

"Remember when you and Rob were breaking up and you lost all that weight?"

"Yeah," I sighed. "I felt terrible and everyone told me how great I looked. Go figure!"

“Well, that’s what’s happening now. We’ve each gained weight as an insurance policy in case our romances break up and we aren’t able to eat. It’s nature’s way of protecting us — at the same time that it's making us look hot for the next guy.”

I looked at her, slightly dumbfounded — admittedly, not my best look. But just as I was about to tell her how ridiculous she was sounding, I realized as weird as it was, she just might be on to something.

Could it be that relationships are the root of our fatness?

It's kind of a cliche that women befriend two guys — Ben and Jerry — when their love life is in the pits.

But studies say that women pack on the pounds or lose them depending on what's happening in our relationships.

We tend to look our best when we're looking for love, which is important because, like it or not, how skinny or fat we are affects a gal's marriage prospects and social mobility more than it does for a man.

But once we start dating — what with all those Frappuccino-quaffing Starbucks quickie online dating meets, trying-to-impress-you fancy restaurant dates and let's-order-Chinese-in-and-watch-a-DVD dates — we gals add about 15 pounds. Move in with your sweetie and it's more like 18 pounds. Get married and suddenly you're packing an extra 24 pounds. And, not surprisingly, if one spouse becomes obese, the other spouse is likely to get fat, too.

This is a very good reason to stay single.

Then, when we're hitched and we should be ecstatic that we're having sex whenever we want, we start getting all freaked about how fat we've become and then we don't even feel like getting it on — let alone how all that extra weight messes with blood flow.

Honestly — the promise of great sex is being wasted on heavy married people!

But just last week, researchers said that women's brains may be the reason we get so fat. Evidently, when we're faced with our favorite foods — say a Dagoba 59 percent dark semisweet chocolate bar — we just can't stop ourselves the way men can.

So, I’ve come up with a diet that is easier and cheaper than any South Beach Diet or Jenny Craig system could ever be. I’m calling it the Kat Wilder Healthy, Happy and Hot Diet because you not only will look great, but you’ll be saving yourself a lot of man trouble, too.

Do daily: Flirt, look for love

In moderation: Dating

Eliminate: Living together — it rarely leads to a successful marriage, almost half of which end up in divorce, anyway. Plus, you’ll be saving all those pounds.

Now, if it’s too late because you’re already married, you have two options — start having lots of sex, which burns off about 53 calories if you can make it last a half an hour, or get a divorce.

And if you do get a divorce, please make it soon — there are going to be a lot of skinny gals out there looking for love.