A Simple Weight Loss Strategy. Really. Maybe.

Dieting and weight control are really pretty simple. We gain weight, and have trouble losing it, because we eat too much and move too little. If we can switch that around, most of us should be able to maintain a sensible weight without resorting to unhealthy gimmicks.

But that’s just the biology of weight control. What about the psychology? Why do we habitually take in too many calories, even when we know those calories are a ticket to obesity and all sorts of chronic diseases?

There are two major reasons for unhealthy weight, according to experts. One is a simple lack of self-control. We live in a society where every day we confront an abundance of high-calories foods. Not overeating in this environment requires extraordinary discipline. The second is an inability to cope with stress. Struggling with ordinary but constant life stresses can drain the cognitive energy needed for discipline, weakening our resolve. Stress-related eating packs on unhealthy calories, contributing to weight gain—and over time to obesity.

What if there were a simple psychological intervention that addressed both of these issues at once—bolstering self-control and buffering against everyday stress?

I know. It sounds like one more gimmick, too good to be true. Perhaps, but in a new study, two psychological scientists propose just such an intervention—along with some preliminary evidence to back it up. Christine Logel of the University of Waterloo, Ontario, and Geoffrey Cohen of Stanford University describe a brief and simple way to give people the tools for resisting temptation and coping with life’s pressures.

It’s called “values affirmation,” and it’s done with a simple writing exercise. The theory is that focusing on one’s core values triggers a cascade of psychological processes: It bolsters a sense of self-worth and personal integrity. It underscores our higher values, rather than our impulses, and by reminding us what’s really important in life, it buffers against mundane stresses. Since stress saps our limited cognitive resources, such an affirmation frees up these resources for willpower and self-discipline.

At least that’s the theory, which Logel and Cohen tested in a simple experiment. They recruited a group of young women (apparently women are more prone to stress-related overeating), recording their baseline weight and Body Mass Index, or BMI. The women were representative of North American women in general. That is, nearly 60 percent were overweight or obese, the rest normal. Notably, all were dissatisfied with their current weight.

Then half of the women wrote an essay about their most cherished values—religious beliefs, relationships, whatever they considered most important to them. The remainder, the controls, wrote about something they did not prize particularly, and why it might be important to someone else. Importantly, none of the values in the exercise had to do with weight or health.

That’s it. That’s the entire intervention. Then the scientists waited for about 2½ months, at which point they called all the volunteers back into the lab. They again measured their weight and BMI, and also their waistlines. They also gave the volunteers a test of working memory, which is one of the cognitive processes crucial to self-control. Reducing stress should theoretically boost working memory capacity and, consequently, discipline.

The results, reported on-line in the journal Psychological Science, were clear and quite dramatic. The control subjects gained 2.76 pounds on average, and this gain boosted average BMI as well. Anyone who has ever struggled with weight knows that this is a huge weight gain in just 2½ months. It’s the equivalent of more than 13 pounds in a year—for no particular reason. By contrast, those who had completed the values affirmation lost an average of 3.4 pounds–also huge–and trimmed their BMI in the process. Women in the values intervention also had smaller waistlines, independent of BMI. And these women also had better working memory, suggesting that it was indeed their enhanced cognitive function that bolstered their self-control. Even the most seriously overweight women experienced these dramatic results after the brief writing exercise.

Losing even a few pounds and keeping them off can be maddeningly difficult. So how could one brief intervention like this have such long-term results? The scientists believe that people can get stuck in repeating cycles, in which failure to lose weight impairs psychological functioning, which in turn increases the risk of more failure. Even a quick and simple intervention has the power to disrupt this destructive cycle.

All right, so let’s be as skeptical as we can here. It’s a small study, just a single experiment with a modest number of subjects. And while 2½ months is a significant chunk of time, we don’t know how these women are doing now—or how well they’ll control their weight over years. Even so, these results are the first evidence that affirming a person’s values can measurably reduce health risk. What’s more, it’s a low-cost, low-effort intervention that could easily be repeated, with at least the possibility of slowing the accumulation of both pounds and risk over years.

Wray Herbert’s book, On Second Thought, is now available in paperback. Excerpts from his two blogs—“We’re Only Human” and “Full Frontal Psychology”—appear regularly in Scientific American and in The Huffington Post.