Poor Research Drives Me Nuts
Written on July 13, 2008 at 10:28 pm, by Eric Cressey
Here is a quote from a Venezuelan researcher in this article:
“Most weight loss studies have determined that a very low carbohydrate diet is not a good method to reduce weight. It exacerbates the craving for carbohydrates and slows metabolism. As a result, after a short period of weight loss, there is a quick return to obesity.”
I’m sorry, but are you kidding me? Does Pubmed not exist in South America? There are dozens of studies out there verifying the incredible value of carbohydrate-restricted diets in improving body composition. And, this is a classic example of a researcher manipulating study design to achieve a desired end. Frankly, I’m amazed that a U.S. university would allow such a poor study design to even be carried out.
They claim that the results show that low-fat, higher carb diets outperform low-carb, higher fat diets when both diets are low in fat and total calories. In other words, the implication is that they are calorically equal – when in fact, the higher carb group received 155 calories more per day (14.3% higher caloric intake). Over the course of the four month study, the low-carb group averaged five pounds more (28 vs. 23) in body weight reductions. At eight months, however, they had regained 18 pounds while the low-fat, higher-carb group had continued to lose weight. It must be the carbs, right? Wrong!
The high-carb group was on a less severe diet calorically, so the rebound should be less. Additionally, the breakdown of their meals during the four-month intervention was different. Most notably, the higher-carb group received 610 calories at breakfast to the low-carb group’s 290 calories. The higher-carb group was also allowed almost twice as much protein (93g vs. 51g) than the low-carb group. I don’t care if it keeps you out of ketosis; protein is satisfying, has a higher thermic effect of food, and has marked benefits on
So, they’ve taken two groups:
Group A: low-carb (lower fiber, as a result), lower-calorie, low-protein, small breakfast, large dinner, and more severe restriction
Group B: higher-carb, higher calorie, higher-protein, large breakfast, small dinner, and less severe restriction
So, we have six factors that are markedly different, yet we can ascertain that one factor (high-carb vs. low-carb) is the reason that some dieters were more successful than others? Bogus research – and the worst part is that since Reuters picked it up, it’ll get more press than all of the peer-reviewed, legitimate research that only appears on Pubmed.
Repeat this study with the same caloric content over the course of the day and at each meal, identical protein consumption, and a zero calorie fiber supplement, and I’ll guarantee that the lower carbohydrate group “wins” 90% of the time.
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July 14th, 2008 at 12:14 am
Good points Eric. Thought I would leave a link to a more proper low carbohydrate article/study.
http://www.ccjm.org/pdffiles/Volek1102.pdf
By Dr. Jeff Volek from the Cleveland Journal of Medicine, Nov. 2002. Found using pubmed!
July 14th, 2008 at 10:43 am
Eric I’d like to see your dietary recommendations for those seeking to reduce body fat and maintain (or possibly increase) strength.
July 14th, 2008 at 11:04 am
Hi Eric, wondering what you think of the “nutrient timing system” approach, are you familiar with it?
July 14th, 2008 at 1:28 pm
I’m from Venezuela and she has a system and a book (shit BTW) to sell, so a ‘study’ was just a matter of time.
Her research is non-existent, and she is definitely not familiar with Dr. Volek or any of the recent work.
Heck, even Atkins had some more legit stuff that her.
July 14th, 2008 at 4:41 pm
I have lost 30 pounds since feb. following a low carb diet. I highly recommend it.
July 14th, 2008 at 11:02 pm
You tend to see this type of thing a lot with nutrition, where the researcher start with a hypothesis, and then takes the necessary steps to prove it right, or similarly, through faulty research comes to a new or controversial conclusion, but doesn’t go back to test their procedures or assumptions – good job on this one Eric –
July 16th, 2008 at 4:02 pm
I don’t know who should be more ashamed: the researcher, the university who greenlighted this crap or Reuters for not having a science journalist or editor read this before publishing.
This is not a journalistic piece, it is a press release. Only one side of the story is told. No experts who may take an opposing viewpoint are presented. Not even the regular, lazy journalistic hack of “some experts say…” is used to provide an opposing viewpoint.
The study design is, as noted, crap. How many variables is this researcher trying to study? Hello? Pick one variable, control the others. That is how science is done. At least proper science, not book-selling, newspaper-hawking, ego-pumping pseudoscience.
Jason Hodges MD
July 17th, 2008 at 7:03 am
Eric has written an article on his views on nutrition on t-nation.
It was written some time back, so he may have changed some views since then:
http://www.t-nation.com/article/performance_training/periodize_your_diet&cr=
July 18th, 2008 at 3:14 am
By what mechanism can a low-carbohydrate diet that is isocaloric with a 'normal' diet increase loss in body weight? Also, I think that it's important to keep in mind one of the last statements in Volek's article which mentions that no long-term, low-carb studies have been done. Here's another study from PubMed in which we see improved health with low-carb but no difference in body-fat loss.
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1368980
I mention this because I'm not sure whether people are discussing health benefits of a low-carb diet including wieght loss or irregardless of weight loss.