It takes a lot of will to successfully lose weight, but a new research review suggests that "motivational" conversations with a health provider may make little difference.
The review looked at studies that tested the effects of motivational interviewing, where a health care provider asks questions to encourage patients to talk about what they'd like to change and why.
The technique is commonly used in health care, to help address issues such as smoking and problem drinking. It has also been incorporated into weight-loss programs that focus on lifestyle changes.
But the new review -- published March 29 in the Annals of Internal Medicine -- discovered little benefit.
Researchers found that when motivational interviewing was folded into weight-loss programs, it did not add much: On average, people lost no more weight over one year than those getting other types of help.
Why? Moscho Michalopoulou, the study's lead researcher, speculated on one potential explanation: Once people are ready for a weight-loss program, their motivation may already be high enough.
Only a few trials in the review looked at the impact of motivational conversations during routine medical checkups, explained Michalopoulou, a dietitian and doctoral candidate at the University of Oxford in England.
But even in those four studies, she said, the approach did not make a difference in people's likelihood of losing weight and keeping it off.
None of that means there's no role for motivational interviewing. It has value, in part, because it's different from simply telling patients what to do, according to Dr. Melanie Jay, who specializes in obesity treatment at NYU Langone Health in New York City.
"If you do it right, it's a conversation," she said, adding that it "puts patients in the driver's seat," and allows them to articulate their goals.
Jay agreed that for people willing to enter a weight-loss study, there might be little room for improvement as far as motivation goes.
But the reality, she said, is that long-term weight loss also requires much more than motivation: Obesity is complex, and many forces that are outside a person's control are at work.
For one, there's genetic susceptibility. "Obesity is as heritable as height," said Jay, who co-wrote an editorial published with the study.
And even though diet and exercise are clearly important, they are not simply a matter of choice, either. "We live in very obesogenic environment," Jay pointed out.
That means, among other things, people are surrounded by fast food and other unhealthy diet choices and lack opportunities to be active. Those issues are particularly challenging for lower-income people, who may live in "food deserts" with few options for healthy eating or have no safe places for exercise, Jay noted in the editorial.
And in general, she said, the human body is designed to resist our efforts to shed weight. When people cut calories, that slows down the body's metabolism and alters the signaling from hormones that govern hunger and feelings of fullness.
"Motivation is important," Jay said, "but it's not enough."
If that all sounds discouraging, she also made this point: Whether you lose weight or not, healthier food choices and regular physical activity can have important health benefits.
And it's important, Jay said, that people not "beat themselves up" over a lack of change on the bathroom scale.
The current findings are based on 46 studies that included over 11,000 people in all, most of whom had obesity. All of the studies used motivation interviewing during counseling sessions on weight loss, healthy eating and exercise. None relied on the technique alone, according to the researchers. It was always part of a set of strategies to support lifestyle changes and weight loss.
Overall, the review found, tactics using motivational conversations were better than nothing -- at least in the first three to six months. People typically lost a few extra pounds.
But motivational interviewing added no obvious benefit, versus behavioral programs that did not use the technique. Over one year, the researchers found, weight loss was "modest" across the studies -- with people again averaging just a few pounds.
Those small weight changes are not surprising. According to Jay, studies show that even in "intensive" weight-loss programs, only half of participants lose at least 5% of their starting weight (a goal commonly recommended for people with obesity).
When lifestyle changes are not enough, Jay said, there are additional options -- including prescription medications that help regulate appetite and food intake. For some people with more severe obesity, surgery may be an option.
The U.S. National Institutes of Health has more on obesity treatment.
SOURCES: Moscho Michalopoulou, RD, MSc, doctoral candidate, University of Oxford, England; Melanie Jay, MD, associate professor, medicine and population health, NYU Grossman School of Medicine, and co-director, NYU Langone Comprehensive Program on Obesity, New York City; Annals of Internal Medicine, online, March 29, 2022