This post is for my dad, who bought me Wheat Belly so that I could read it and tell him what I thought of it.
WHAT’S GOOD ABOUT THIS BOOK?
1. Just as Born to Run questioned (in its entertaining but overblown way) whether we should trust shoe companies to tell us what our footwear needs are, this book advocates a healthy skepticism regarding agribusiness-influenced nutritional guidelines.
2. The book may help some people understand celiac disease and gluten-free diets. I hadn’t previously read much about gluten and was pleased to discover details about the gliadin and glutenin proteins which comprise it.
3. Likewise, I was pleased to read about wheat’s history of genetic and morphological changes, which author William Davis discusses in detail. Even if the health implications of these changes are debatable, it’s interesting to contrast the ancient einkorn wheat (14 chromosomes) and emmer wheat (28 chromosomes) with modern dwarf Triticum species (42 chromosomes).
4. There may be some truth to at least one of the author’s provocative assertions, i.e., that the breeding of wheat for more optimal baking properties may have contributed to the rise in celiac disease (van den Broeck et al. 2010).
WHAT’S BAD ABOUT THIS BOOK?
1. The central message — that wheat is evil — is irrationally and offensively simple-minded. There are a few surprising nuances in the book, such as the admission that the wheat hybridization work of Norman Borlaug helped solve the problem of world hunger. Yet Davis continually returns to his “wheat is evil” rhetoric without apparent hesitation or irony.
2. The language is often hyperdramatic at the expense of clarity and accuracy. For example, Joe Schwarcz (2013) bemoans the way wheat is blamed for osteoporosis because of its production of (tiny amounts of) sulfuric acid. “Davis panics readers with totally irrelevant statements about sulphuric acid causing burns if spilled on skin,” Schwarcz says. “Get it in your eyes and you will go blind. True, but what does that have to do with traces formed in the blood from cysteine?” Melissa McEwan (2011) accuses Davis of “anti-technology scare-mongering, preying on the agricultural ignorance of the average consumer.” She notes, “Telling me … that wheat has ‘undergone extensive agricultural genetics-engineered changes’ is hardly terrifying to me, as this describes almost all seeds on the market today.”
3. Davis writes with smug confidence about the devastating effects of wheat on human health, yet the scientific evidence for many of his claims is weak, misrepresented, or nonexistent. Pete Bronski (2012) dissects three examples of Davis’s misuse of the biomedical literature; additional examples are below.
WHAT ARE THE CENTRAL CLAIMS MADE BY THIS BOOK, AND HOW REASONABLE ARE THEY?
Wheat Belly makes numerous claims. Below are five that I personally consider important, along with some comments about their validity.
1. Wheat is unique in elevating blood sugar to unhealthy levels.
There are two issues here.
First, wheat products do not have an exceptional, uniformly high Glycemic Index (GI), the standard measure of glucose release into the blood. As McEwan writes, “If there is something special about wheat spiking blood sugar, why do some wretched coarser breads measure in the low thirties and forties (lower than many fruits and sweet potatoes), and so many gluten free breads measure so much higher? Davis mentions that the latter is often made from extremely refined processed rice, tapioca, and corn. And thus we have the answer — highly digestible carbohydrates, no matter what their provenance, are high glycemic.”
A second issue is that the GI of any carbo-rich food, including wheat, can be reduced by eating it with protein and fat. Davis describes a personal experiment in which he ingested four ounces of organic whole-wheat bread, and, sure enough, his blood glucose rose a lot. But who (other than my Uncle Scott) eats large quantities of low-fat bread, all by itself, in one sitting? It’s a pretty artificial situation, and one that is easily remedied by the addition of some peanut butter or meat or whatever.
2. Wheat is addictive.
There are multiple reasons to question this claim, which is based on the idea that wheat protein gets broken into peptides known as exorphins, which act on the brain as opioids.
First, exorphins released from wheat cannot exit the gastrointestinal tract without being further digested into non-drug-like molecules. Fred Brouns et al. (2013) explain: “Gliadorphin consists of seven amino acids (Tyr-Pro-Gln-Pro-Gln-Pro-Phe) and, as such, cannot be absorbed by the intestine. This is because the intestine peptide transporter PepT1 transports only di- and tripeptides (Gilbert et al., 2008) and transporters for larger peptides have not been identified. Gliadorphin is therefore not present in intact form in the human circulatory system and cannot reach and have an effect on the cells of the central nervous system.”
Second, as covered by Julie Jones (2012), proteins from milk and other sources yield exorphins too, so wheat is not unique in this respect (Jones 2012).
Third, Jones (2012) also points out that gluten stimulates the release of the hormones cholecystokinin and glucagon-like peptide 1, which contribute to a feeling of fullness or satiety. This is contrary to the vicious cycle proposed by Davis, in which ingesting some wheat leads to a craving for more.
3. Wheat causes obesity. Eliminating it leads to weight loss.
Michael Casper (2012) summarizes the evidence as follows: “We have to take Davis’s word that his anti-wheat diet works, because most of the cases of weight loss and recovery from illness are from his own practice.”
Jones (2012) and Brouns et al. (2013) also cite a paper from the Framingham Heart Study (E.A. Molenaar et al., Diabetes Care 2009) showing a negative correlation between whole-wheat consumption and risk of obesity. While this finding of a correlation is not a smoking gun, it is the opposite of what Davis would predict.
If wheat itself was a cause of weight gain, replacing wheat with an equivalent number of non-wheat calories would lead to weight loss. No controlled peer-reviewed study along these lines is cited by Davis; perhaps he should use some of his book royalties to finance one.
4. Wheat contributes to many other diseases besides diabetes and obesity (autism, schizophrenia, etc.).
Davis devotes full chapters to wheat’s effects on the body’s pH (Chapter 8), advanced glycation end-products (AGEs) (Chapter 9), heart disease (Chapter 10), the brain (Chapter 11), and skin (Chapter 12). There is no concise way to address all of these, but, as examples, Chris Masterjohn (2011) pokes many holes in Davis’s stories about pH and AGEs, and Jones (2012) notes a lack of strong links between wheat and autism, ADHD, or schizophrenia.
Casper (2012) adds, “Davis’s claims about wheat and schizophrenia are based on very old papers -– nothing within the past 25 years -— and this is another example of an abuse of definitions in order to further an anti-wheat agenda.”
5. Modern wheat is the product of science crossbreeding experiments. Its safety has never been tested.
Davis does not define the safety tests that he thinks are absent but needed. Apparently he considers observational studies inadequate and would prefer clinical trials (i.e., much stronger evidence than he uses to support his wheat-is-evil hypothesis). In any case, he misleads us with his implication that crossbreeding leads to radical, unpredictable, likely-to-be-dangerous changes.
For example, Davis says, “Analyses of proteins expressed by a wheat hybrid compared to its two parent strains have demonstrated that, while 95 percent of the proteins expressed in the offspring are the same, 5 percent are unique, found in neither parent.” However, his reference (Xiao Song et al., Theoretical and Applied Genetics 2009) simply reports that parents and offspring differ in the amounts of some of the proteins they produced, not changes in which proteins were present. Davis: “In one hybridization experiment, fourteen new gluten proteins were identified in the offspring.” Reality: the 14 proteins were slightly mutated versions of parental proteins, not completely new ones, and the study cited (Xin Gao et al., Planta 2010) involved somatic cell hybridization, a complicated laboratory technique not typically used by wheat breeders (NWIC 2012). Davis: “The genetic modifications created by hybridization for the wheat plants themselves were essentially fatal, since the thousands of new wheat breeds were helpless when left to grow in the wild.” Reality: yes, a plant that once grew in the wild has been adapted for domestic food production. The varieties now optimized for food production are no longer optimized for surviving in the wild, and thus do not thrive outside farms. This is neither surprising nor worrisome nor unique to wheat.
Finally, while other grains have also gone extensive optimization, Davis does not comment once upon the changes to the genomes of corn, rice, etc. In Casper’s (2012) words,
Davis argues in the second chapter of Wheat Belly that wheat has been genetically modified in the past few decades beyond all recognition, and this modification is somehow the source of the danger that wheat poses to us. It is a cunning argument, because it is certainly the case that genetic modification has taken place, and it is difficult to disprove that such changes have been harmless. But why stop at wheat? Corn, for instance, has certainly been subjected to dramatic genetic modification, as discussed in a 2003 article from the journal PLOS Biology. Why single out the genetic modifications of one crop, and not consider the implications of all the others? Or is Corn Belly intended as a sequel?
CONCLUSION
Wheat Belly offers a simple, seemingly research-based solution to a myriad of ailments. It has proven tremendously popular, especially among low-carb advocates. However, its narrative is based on “cherry-picked data, inflammatory hyperbole, misused science, irrelevant references and opinion masquerading as fact” (Schwarcz 2013). As such, it is hardly the slam-dunk case against wheat that it purports to be.
REFERENCES
Pete Bronski. Wheat Belly, busted. No Gluten, No Problem (blog), March 20, 2012.
Fred J.P.H. Brouns, Vincent J. van Buul, and Peter R. Shewry. Does wheat make us fat and sick? Journal of Cereal Science 58: 209-215, 2013.
Michael Casper. Wheat Belly, a book review. Caspersfarm’s Blog, September 13, 2012.
Julie Jones. Wheat Belly — an analysis of selected statements and basic theses from the book. Cereal Foods World 57(4): 177-189, 2012.
Chris Masterjohn. Wheat Belly — the toll of hubris on human health. The Daily Lipid (blog), October 12, 2011.
Melissa McEwan. Wheat Belly. Hunt Gather Love (blog), October 8, 2011.
National Wheat Improvement Committee (NWIC). Wheat improvement: the truth unveiled. USDA.gov (website), 2012.
Joe Schwarcz. Wheat Belly gives me a belly ache. McGill Office for Science and Society (blog), June 29, 2013.
Hetty C. van den Broeck et al. Presence of celiac disease epitopes in modern and old hexaploid wheat varieties: wheat breeding may have contributed to increased prevalence of celiac disease. Theoretical and Applied Genetics 121(8): 1527-1539, 2010.
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