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Recap of mental imagery for weight loss study makes readers fill in the blanks

Weight loss can be boosted fivefold thanks to novel mental imagery technique

Our Review Summary

The news release focuses on a study reporting that overweight individuals who engaged in functional imagery training (FIT) were more successful at losing weight than individuals who engaged in a type of talk therapy called motivational interviewing (MI). However, the release does not answer many questions that are relevant to determining how useful FIT is for weight loss. For example, because the study does not appear to have collected information on diet or exercise, it’s not clear whether the difference in outcomes stems from differences in lifestyle choices made by study participants.

It would have been helpful if the release (and study) had analyzed specifically how increased motivation and lifestyle choices can result in weight loss. The published study notes that data relating to “participants’ experiences and process variables, including frequency of motivational cognitions, self-efficacy for diet and physical activity, self-reported diet and physical activity” were collected but that the results would be reported separately.


Why This Matters

When comparing the efficacy of MI and FIT, it’s important to know what sort of lifestyle changes study participants made. If a significant percentage of participants who engaged in FIT also joined a for-profit diet program, that support system might explain the differing results. By the same token, it’s not clear if the MI group and the FIT group were matched for initial weight, sex or age — any of which could influence how much weight was lost. Without knowledge of those details, it is difficult or impossible to say how much more effective FIT was than MI (if at all).

According to the published research, there were some differences in full-time employment and the range in baseline weight that weren’t addressed in the limitations section of the study and which could affect the reliability of the data.


Does the news release adequately discuss the costs of the intervention?

Not Satisfactory

Both MI and FIT rely on patients engaging in multiple sessions with a trained therapist. Whether done in a for-profit country like the United States or a country that partially or fully subsidizes health care, there are cost considerations. The cost of those sessions, and follow-up consultations, was not mentioned.

Does the news release adequately quantify the benefits of the treatment/test/product/procedure?


The release describes benefits in terms of kilograms lost at six months and twelve months after the FIT/MI intervention. Benefits are also described in terms of centimeters lost from their waist circumference. This information would have been more meaningful if it had provided information about the starting weight and waist circumference for the groups, since that would have shed light on whether one group would find it more difficult to shed kilograms or centimeters.

Does the news release adequately explain/quantify the harms of the intervention?

Not Applicable

Some forms of weight loss can pose risks for patients, such as various fad diets or when people with a sedentary lifestyle suddenly begin engaging in rigorous exercise. But this study does not appear to have evaluated how people tried to lose weight, instead focusing on the extent to which they were motived to make changes based on the intervention. Because of the nature of the study, we’ll rate this as not applicable. However, it would have been valuable to include language encouraging people to talk to a health care provider before making abrupt changes to their lifestyle.

Does the news release seem to grasp the quality of the evidence?

Not Satisfactory

The release does a fairly good job of describing the study design. However, as noted above, some crucial information is missing. Did the FIT and MI groups have comparable numbers of men and women? Were the groups comparable in age? Were the groups comparable in terms of overall health? Essentially, the release should make clear whether the researchers were comparing apples and oranges. What’s more, it would be important to know what steps the people in each group took to lose weight. If both groups consisted of comparable demographics AND both consisted solely of people who started watching what they ate and engaging in more light exercise, then the hypothesis holds that FIT was responsible for the difference in outcomes. But even if both groups were comparable demographically, but one group happened to adopt a different weight loss approach, that could account for the difference. In other words, it’s possible that some unknown variable was responsible for the FIT group’s success — because it’s not clear whether the study controlled for that. The release specifically notes that the study did not dictate how study participants chose to lose weight. But the study should still have tracked what those efforts looked like, in order to determine FIT’s role in the weight loss.

Does the news release commit disease-mongering?

Not Satisfactory

Weight loss is not inherently good. The release refers, once, to study participants as being “overweight,” but it’s not clear what they mean. Are these people who could stand to lose a pound or two? Or are they morbidly obese? It is possible to be both healthy and “overweight,” depending on how you define those terms. In the paper, they define “overweight” as having a body mass index (BMI) of greater than or equal to 25. Having a BMI of 25 puts you exactly on the borderline between “normal” and “overweight” — and the BMI itself is a very incomplete means of measuring an individual’s body fat and assessing health.

Does the news release identify funding sources & disclose conflicts of interest?


The funding source is clearly identified. There are no apparent conflicts of interest, though the release would have been stronger if it had addressed this directly.

Does the news release compare the new approach with existing alternatives?


The release addresses this, sort of, when it states: “Most people agree that in order to lose weight, you need to eat less and exercise more, but in many cases, people simply aren’t motivated enough to heed this advice – however much they might agree with it. So FIT comes in with the key aim of encouraging someone to come up with their own imagery of what change might look and feel like to them, how it might be achieved and kept up, even when challenges arise.” That’s enough to earn it a satisfactory ranking, particularly since it is consistent with the underlying study. However, it would be more valuable to see how effective FIT is when used in conjunction with proven weight loss techniques.

Does the news release establish the availability of the treatment/test/product/procedure?

Not Satisfactory

The release describes FIT as a “new motivational intervention.” Is it in widespread use? How difficult would it be for someone to find a practice that can provide FIT for weight loss? The release doesn’t address this.

Does the news release establish the true novelty of the approach?


The release refers to FIT as “novel” and “new” — but (as noted above), researchers have been publishing on FIT since at least May 2016. We’ll give the release the benefit of the doubt here since reasonable people can disagree on what constitutes novelty or “new-ness.”

This 2016 paper looked at the use of FIT to inform dietary choices for people who wanted to lose weight. The new paper appears to be the first to look specifically at weight loss, but that context is missing since the release does not place the work in context with other research in the field.

Total Score: 5 of 9 Satisfactory


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