Sometimes I just have to roll my eyes when I hear about nutritional experts rating diets. The reason is that apparently none of the “experts” actually reads the published data critically. Undoubtedly, one of the worst offenders is the annual U.S. News and World Report study on diets. After watching them year after year making the same unsupportable statements, I finally tried to educate the editors before the 2015 rankings appeared. Not surprisingly, I found all the same mistakes were still there.
Let me list what they wrote and my comments that I made to each of the sections that somehow never got included.
Will you lose weight?
What limited research there is on Zone suggests it’s moderately effective for weight loss.
Research is scant but does suggest that the Zone diet could help the heart by bringing down cholesterol levels and reducing inflammation.
There is some evidence that suggests that the Zone can be beneficial as it lowers inflammation in type-2 diabetics.
Finally, throughout the article, they continually refer to a “A review of the Zone diet published in 2003 in the Journal of the American College of Nutrition that concluded that scientific evidence ‘casts strong doubt’ on its health claims and theory.”
I sent them the following response (in red) that also seems to have fallen into the U.S. News and World Report wastebasket.
Apparently a “review” article was written more than a decade ago by a researcher employed by the U.S. Army that questioned the scientific validity of the Zone Diet (1). Since this review article was published in 2003, I will initially focus on the published peer-reviewed research available before 2003 that demonstrates the reviewer’s complete lack of any command of the available scientific literature that makes all of his conclusions totally invalid.
The author’s key point is “there are no peer-reviewed scientific data on the Zone Diet” (1). That is simply a false statement (2-5). Specifically, researchers at Harvard Medical School published a carefully controlled study demonstrating that a single meal following the composition of the Zone Diet dramatically altered the secretion of insulin and glucagon in a single meal as predicted (3). In addition, the subjects in that trial consuming the meal following the composition of the Zone Diet demonstrated significant reductions in their calorie consumption at the follow-up meal compared to consuming control meals of equal calorie intake. In 2000 the same Harvard investigators demonstrated that the Zone Diet had a similar effect on the reduction of appetite as well as a superior effect on resting energy expenditure compared to the control diet under hypocaloric conditions (4).
The author of that review also appears not to be familiar with other studies published more than a decade before his review that demonstrated hyperinsulinemia accelerates the activity of the enzyme delta-6 desaturase that converts dihomo-gamma linolenic acid into arachidonic acid (5,6). This increase in arachidonic acid would produce more “bad” eicosanoids, which is one of the fundamental themes of the Zone Diet. This published data more than a decade earlier rebuts the basic arguments of his “review”. The ignorance of this published information is difficult to understand since the references on the role of insulin and increased arachidonic acid formation were included in The Zone (7). Perhaps Mr. Cheuvront never read the book he was criticizing.
In addition, Mr. Cheuvront fails to mention that my book, The OmegaRx Zone, published in 2002, went into extraordinary detail on the role of omega-3 fatty acids to further alter eicosanoid levels (8). I should point out that the same book essentially launched the world-wide fish-oil revolution as it demonstrated the potential of high-dose fish oil to further alter eicosanoid levels in conjunction with the Zone Diet.
After Mr. Cheuvront’s review was published in 2003, it should again be noted that in 2007 the Joslin Diabetes Research Institute at Harvard Medical School published its dietary recommendations for treating obesity and type-2 diabetes (9). Those dietary recommendations are essentially identical to the macronutrient composition and caloric content of the Zone Diet. Joslin researchers confirmed the efficacy of those dietary recommendations with a clinical trial using the Zone Diet with type-2 diabetics (10). In addition, a significant number of carefully controlled articles have been published since 2002 that support the efficacy of the Zone Diet in treating metabolic disorders (11-16).
It is a sad commentary that I have to answer the “critique” of an individual who demonstrated a very limited understanding of the published scientific literature and the clinical trials that support the Zone Diet, but I hope this short overview addresses the obviously incorrect conclusions of his poorly researched “review” that is constantly referred to in the annual rankings.
The Zone Diet was developed to reduce inflammation. It is the only diet that has been consistently demonstrated to do so in clinical trials. I can only assume the reduction of inflammation is not considered an important benefit of the Zone Diet by the nutritional experts used by U.S. News and World Report.
Maybe some time in the future the editors and their “experts” may actually read the articles that I quoted to them. If they do, then they are likely to come to the same conclusion as the Joslin Diabetes Research Center that the Zone Diet is your best lifetime diet choice if the goal is to reduce inflammation.
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