An incorrect opening sentence in the original version of the story (apparently corrected later) was the only significant flaw we found with this story.
People want to believe that there’s a diet that will make it easier for them to shed pounds and keep them off over the long term. And this JAMA study does provide some evidence to support the superiority of diets with lower carbohydrate content and more protein for weight loss maintenance. However, just a few months ago, the same journal was trumpeting the findings of a study that appeared to show just the opposite — i.e. that “a calorie is just a calorie” and that the source of the energy (fat, protein, or carb) doesn’t matter. So we need strong health reporting to be able to make sense of these competing claims.
The cost of these diets is not really in question. We’ll call it not applicable.
The opening sentence of this story as originally published is incorrect. It states that dieters “were more successful maintaining weight on a low-carb diet than they were on a low-fat diet.” According to the study, there was no statistically significant difference in participant weights during the 3 diet phases. The main finding was that participants resting energy expenditure was increased during low-carb and low glycemic-index phases than during the low-fat phase, which might theoretically improve weight loss maintenance. The story did do a good job of characterizing the difference in energy expenditure between the 3 diets and what it would take to burn the same amount of energy via physical activity.
[Note: the incorrect opening line appears to have been pulled from an updated version of the story.]
The story notes that the low-carb diet raised some risk factors for heart disease.
Caveats are introduced high up in the story and, unlike the competing WSJ coverage, USA Today provides 3 independent perspectives on the findings. Two of these experts mention important limitations, including the fact that the study was short-term and conducted under highly controlled conditions.
The story provides comments from 3 outside experts who have differing takes on the research. It notes that one of the experts is the author of an Atkins diet book.
The focus of the story was on different dietary approaches to weight loss.
The availability of the 3 diets is not question.
The independent experts allude to the fact that there have been other studies that found no difference in weight loss between diets with varying proportions of fat, protein, and carbohydrate.
The story is not based on a press release.