Can losing weight really be as simple as a 15-minute writing session? It worked for a group of women who recently took part in a psychological study. But it depends on what you write about.

Women who wrote about their most important values for 15 minutes lost an average of 3.4 pounds over the next few months. Women who wrote about something less important gained an average of 2.8 pounds.

The researchers speculate that writing about one's values can kick off a chain reaction.

The researchers think the weight loss was due to increased self-affirmation or self-esteem. Writing about their values made the women see themselves as better people and feel better about themselves. It may also serve to strengthen resolve. Often, heavy eaters eat in an attempt to elevate their mood. Who hasn't felt better after eating a brownie? But some people take this to an extreme and over time, the pounds can add up.

The researchers speculate that writing about one's values can kick off a chain reaction. It starts when writing about an important value makes you feel better about yourself. Maybe when you go home that night and skip the brownie or cookies you've been using as an emotional crutch. In time, skipping the brownie becomes a habit.

The study looked at 45 female undergraduates who were on the heavy side or overweight. Their average BMI was 23 — normal weight is 18-24.9; higher BMIs are considered overweight. Most of the women (58%) were either overweight or obese.

Each woman was weighed, and was then given a list of important values, like creativity, politics, music, and relationships with friends and family members. Each woman ranked these values in order of personal importance. Then half the women were told to write for 15 minutes about the value that was most important to her. The other half were told to write about why a value far down on their list might be important to someone else.

The women came back between one and four months later to be weighed again. The results speak for themselves.

It's not known if everyone will get such good results. This study was only of a small number of a certain type of person -- female college students. And while the women didn't know the object of the study, they may have wondered why they were being weighed for a psychology study. But the idea is certainly easy enough to test out for anyone who's battling a weight problem. All it takes is pen and paper (or word processor) and a little introspection.

You've tried tummy crunches. You've tried the grapefruit and cauliflower diet. What's to lose from trying 15 minutes of writing?

The study is published in Psychological Science.