What has happened to nutrition research: Carbs versus fat?

Are these carbs equal?  Photo by Wendy Copley

Are these carbs equal? Photo by Wendy Copley

It used to be that when I came across scientific research, the best way to begin judging the merits of the study was to look at whether the investigation was published in a peer-reviewed journal. This means that a group of scientists with knowledge about the specific topic of the study would assess how it was done and whether it represented good science.

Issues such as bias on the part of the researchers or whether the subjects truly represented the  group being studied – in other words, the basic design of the research project was evaluated. If they passed muster by this group of peers, then the journal would publish the research.  Then health professionals such as myself could believe that research.

But alas, it appears that those days are gone.  More and more studies  with less than credible design seem to be able to make it to the pages of respected scientific journals. Witness those involving  breakfast  skipping last week.

This week leads us to this week’s study, Effects of Low-Carbohydrate and Low-Fat Diets: A Randomized Trial, published in the prestigious Annals of Internal Medicine.

It concludes, “The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors.”

The media, once again, has jumped on the study as the new gospel. Check out, “A Call for a Low-Carb Diet That Embraces Fat”  in the New York Times.

It sounds pretty straightforward, doesn’t it?

Not so fast.

If you read what knowledgeable experts, like Dr. David Katz, think  about the study, you might think twice.  In his critique entitled, “Diet Research, Stuck in the Stone Age”, you get a different perspective.

When assessing the two groups, he found that the low carb diet was indeed that. But the “low fat diet was, for starters, not much lower in fat than the typical American diet, which as we all know- is basically crap. Shockingly, the fiber intake was virtually identical, at about 15-16 grams per day, in both groups throughout the study.”

He goes on to say that for the low-fat group to eat so little fibre, they must have been consuming  “preferentially crummy foods made mostly from refined starches and added sugars. …   but it’s clear that the low fat diet was (A) not low fat; and (B) rather crummy. So another title option was: “a comparison of the best low-carb diet to the worst low-fat diet we could come up with.” Again, I think it’s clear why they didn’t go with that one.”

He concludes, “Not relevant, because this was a study designed to generate a predictably useless, misleading, and potentially harmful answer to an egregiously silly and perhaps even willfully disingenuous question.”

It seems that nowadays you need to look at all nutrition research and take it with a grain of salt.

How unfortunate.

What’s your take on this study? Please share in the comment section below.

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Categories: Nutrition News, Rosie's Rants

Author:Rosie Schwartz

Rosie Schwartz is a Toronto-based consulting dietitian and writer.

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4 Comments on “What has happened to nutrition research: Carbs versus fat?”

  1. September 3, 2014 at 9:18 pm #

    Great post, Rosie! I was thinking about this study today as I seen a number of friends sharing it on facebook. It got me confused as well! It’s a tough world to be a Registered Dietitian in, with social media confusing our audience, isn’t it?

  2. September 4, 2014 at 7:30 am #

    Thanks for your feedback, Nicole! Yes – it is indeed tough! But it wasn’t just social media fuelling the confusion. It was the regular media, big outlets such as the New York Times and others who didn’t have perspectives from scientists like Dr. David Katz who can dissect the research.

  3. September 7, 2014 at 2:33 pm #

    I agree with you Rosie – I am battling not only the lack of evidence for long term weight loss, but athletes thinking they can train and compete on ketones (ie very low carb and high fat!!). I attached a systematic review to Judy Barnes Baker comment which does not support low carb. Now that I am fully submerged in my PhD I am more aware than ever of the “media sensationalism” and why we need to critique research methodology (always!!) and David Katz is bang on! And not all carbs are equal as you said…

    • September 7, 2014 at 7:49 pm #

      Thanks for your comment, Nanci! It is really unfortunate that athletes are getting caught up in the misinformation and having their performance affected. But it’s not just “media sensationalism”. I used to think so until I saw a PR release from a university which was actually more sensational than the media. The scientists who are doing this questionable research often want this kind of attention. The University of Western Ontario and a study on eggs comes to mind. We need to keep battling on!

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