Intuitive Objectivity?

Is objectivity possible in the study of intuitive eating? A new study by Janell Mensinger and colleagues published in Appetite might make you wonder. This study randomized 80 women to a controlled trial of a weight-neutral (the HUGS Program for Better Health) versus a weight-loss intervention (the LEARN Program for Weight Management). At the end of a six-month intervention and again after 24 months, a wide range of health and quality of life measures were collected. The authors reported that:

At post-intervention, the weight-neutral program had larger reductions in LDL cholesterol and greater improvements in intuitive eating.

They concluded:

These findings highlight that numerous health benefits, even in the absence of weight loss, are achievable and sustainable in the long term using a weight-neutral approach. The trial positions weight-neutral programs as a viable health promotion alternative to weight-loss programs for women of high weight.

A careful reading of the study suggests that the authors might be overstating the significance of their findings. In this paper, the authors do not explicitly define a primary endpoint for their study. They do, however, say “at 24 months we predicted the weight-neutral program would have sustained more health and well being improvements than the weight-loss program.”

If that statement was meant to define the study’s primary endpoint, then the weight-neutral intervention did not deliver the intended benefit. The investigators found no differences between the two interventions after 24 months.

Another perspective can be found in the ClinicalTrials.gov database. A virtually identical trial led by the same investigator is registered here. If this is the same trial (we are left to guess because the authors do not disclose their ClinicalTrials.gov identifier), then the primary endpoints were systolic and diastolic blood pressure. Neither intervention had an effect on blood pressure. With blood pressure as the primary endpoint, again, the weight neutral intervention did not deliver the intended benefit.

With no demonstrable effect on a primary endpoint, it appears that the authors have tested for an effect on an array of secondary endpoints. They found only two differences that favored the weight neutral intervention at the end of six months: LDL cholesterol and intuitive eating.

The problem is that when you go fishing through a large amount of secondary data, you are likely to find differences by mere chance. According to Distinguished Professor David Allison of the University of Alabama at Birmingham:

When multiple comparisons are tested in a large dataset such as this, statistical multiple testing corrections can help place the significance of the results in perspective. According to the data that have been published here, it appears that the differences between the two treatment groups would not be significant if a Bonferroni correction were used.

So we are left to wonder about the objectivity of the claims in this paper. The investigators apparently set out to prove the superiority of a weight-neutral intervention for people with a high BMI. They did not.

We agree with the authors when they “recommend a cautious interpretation of the results” they have published. The concepts of intuitive eating and a weight-neutral approach to managing obesity may have real benefits in some clinical situations. But strong evidence from rigorous studies is still lacking.

Click here to read the study.

Subjective Impressions of Newcastle upon Tyne, photograph © Sam Leighton / flickr

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June 15, 2016