Dumb study is dumb

This post isn’t even going to be long. This post is just to point out the stupidity of this recent study that’s been getting lots of play in diet circles.

According to headlines, LOW CARB DIETS ARE BETTER FOR WEIGHT LOSS THAN LOW FAT DIETS! Stop the presses. We’ve solved the eternal mystery.


I looked at the full study. Clear as day, right there in the tables: the Low-Carb group was eating fewer calories than the low fat group. 150 calories less a day, on average. A 150 calorie deficit a day would produce a weight loss of about 15 pounds over a year.

People who ate fewer calories lost more weight?




How did this study even get published?


I didn’t feel this study deserved much blog attention. But Dr. David L Katz and James Fell have given it a more thorough thrashing.

9 thoughts on “Dumb study is dumb

  1. Oh basic science education in the public schools, whither has thou gone? Just a beginner level knowledge of the scientific process could short circuit so much of this jackassery.

  2. Yes, they ate fewer calories but I think the most sane take away is that the when the participants ate more fat and fewer carb they were less hungry and therefore ate less overall. When I eat moderate to high carbs and low fat, I am hungrier and end up eating more overall. There is nothing magical about less carbs. It’s about finding a food combination that leaves you satiated yet able to eat at a calorie deficit be it less carbs and more fat , more carbs and moderate fat or any combination in between. I don’t read it as a dumb study, just as a presentation of a possible food combination method that may help you eat at a calorie deficit. The problem is a one size fits all mentality.

    • “I think the most sane take away is that the when the participants ate more fat and fewer carb they were less hungry and therefore ate less overall”

      yes, I totally agree. That is the sane, and quite obvious, takeaway. Which is why it boggles my mind that the researchers didn’t acknowledge it. '?

      • Although it’s worth noting that the low-carb group’s calorie intake did increase over the course of the study, so the sating effect of more protein doesn’t look to be permanent, and without attention to the *actual* reason for the weight loss (decreased calorie intake), it’s unlikely that the effect would continue long term.

        Which is why it’s SO important to tell the whole story.

      • When you publish a study you have to have backup for everything, and you can’t make leaps of assumption like that or insert opinions because it’s really just a guess and not what the data actually show. If you look at the appendix table 3, you will see that there were not enough patients reporting decreased appetite to even calculate a p value. This is probably why it wasn’t mentioned in the paper, the reviewers probably wouldn’t allow it because that’s not what the data show. The calorie difference was not by design, it’s just how people ended up eating after the group assignment and if you calculate it out, there’s not even a statisically significant difference between the two, plus look at the standard deviations. I don’t really like the results either, but this was a pretty well designed study with good quality control and efforts to account for self reported data and it addresses a question that many people have. I also like that they included RD’s on the team. A lot of people put a lot of work into this study and as per usual, the media is picking what they like and running with it and bloggers are picking teams of love it and hate it.

        • The calorie difference between the groups was enough to produce as much as 15 pounds of weight loss over the course of the year. In the discussion of why the low carbs diet produced weight loss, the lower calorie intake wasn’t acknowledged. This is what the researchers said about the weight loss:

          “The underlying mechanisms that may ac-
          count for differences in weight loss by diet are still not fully identified, but a recent study indicated that low-carbohydrate diets may have a more favorable effect on resting energy expenditure and total energy expenditure than low-fat diets ”

          In other words, they’re saying, ‘well we’re not sure why they lost more weight, but speculate it may be because they were burning more calories’.

          Uh…no. they were consuming fewer calories.

          • Unfortunately, studies are limited by analysis and in this study, the difference in calories between the two groups at 12 months is not significant, so that assumption can’t be made. We as readers, bloggers, writers, etc can say that, but they can’t in the paper because it’s not shown in the data. If they said the low carb group ate fewer calories, they’d have to prove it by giving a significant p value corresponding to the difference in means, and they can’t do that because the p value is not significant. That’s probably why it wasn’t said. That’s all '?

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