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Low-carb, low-calorie diets can both result in weight loss


3 Star

Low-carb, low-calorie diets can both result in weight loss

Our Review Summary

The story did an adequate job of quantifying benefits, but does not address harms or costs. The story also allows a questionable quote from one "outside expert" who clearly has a potential conflict of interest with a book he’s promoting.


Why This Matters

  The story matters because people are always looking for a less difficult answer to the issue of excess weight and  they are often confused about which diet is ‘best’ for weight loss and for health.


Does the story adequately discuss the costs of the intervention?

Not Satisfactory

There was no discussion about how the different food consumption patterns compared in terms of price. Is there a difference?  Does cost not matter in such decisions? 

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


 The story did a good job reporting the average weight loss observed in the two diet groups.  It might have been useful to readers to understand how variable the weight loss was in the two groups.  From what was presented, it isn’t possible to figure out whether most people in both groups may have lost about 24 pounds in one year or whether there was variability in the amount of weight loss.

Although the story mentioned that this weight loss resulted in ‘improvement in many health measures’ the study was too short in duration to observe any differences in health outcomes.  Part of the story here was that the low-carbohydrate diet approach to weight loss did indeed result in weight loss. Longer-term study is needed to understand whether there are health implications associated with either dietary approach. 

The story also mentioned "those in the low-carb group had about two times better improvement in their good (HDL) cholesterol than people in the low-fat group."  This is an inadequate amount of information to judge whether this constitutes a meaningful difference between the groups. This result should have been reported as an absolute difference rather than a relative difference.  See our primer on this topic. Rather than report simply on this surrogate end point, do we know anything about what these HDL changes mean  in terms of their risk of heart attack?

We’ve already graded the story unsatisfactory in the "Evidence" criterion so we’ll give it the benefit of the doubt on this criterion.

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

There was no discussion about potential harms or any indication about the percentage of individuals who dropped out of the study.

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

 The story reported study found that the weight loss and maintenance of that weight loss was similar for the two groups.  It provided the average weight loss in pounds giving readers a real sense of the magnitude of the weight being discussed.  This aspect of the story was well done.

But after all these years and all these debates, was the evidence sufficient enough to settle the debate once and for all?  Do we no know, based on this study, that these diets are equivalent? Or is more research needed? These fundamental questions weren’t raised or answered.

Does the story commit disease-mongering?


 The story did not engage in overt disease mongering.

Does the story use independent sources and identify conflicts of interest?

Not Satisfactory

The story did quote several seemingly independent experts on weight loss, along with a clinician involved with the study.  However – they also allowed a clinician promoting his book to also promote one of the diets without challenging his assertions.  It s unacceptable to allow him to make claims for greater weight loss in his experience without providing data to support his contentions. 

Does the story compare the new approach with existing alternatives?

Not Satisfactory

 The story did not include a comprehensive list of evidence based methods for weight loss.   The story lacked a discussion about the essential role of caloric intake, even within the low-carbohydrate diet group.  

Does the story establish the availability of the treatment/test/product/procedure?


 The story reported on outcomes of a study that followed individuals assigned to either a low- carbohydrate or low-fat diet.  Both of these dietary approaches to weight loss are well known and widely used.

Does the story establish the true novelty of the approach?


  The story was clear about the fact that the dietary approaches for weight loss that were compared are not new or novel.

Does the story appear to rely solely or largely on a news release?


 Does not appear to rely exclusively on a news release.

Total Score: 5 of 10 Satisfactory


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