In Part 2, Julie Jones analyzes topics in the book Wheat Belly by William Davis such as the glycemic index, wheat addictions, mood alterations, and genetically altered wheat.
Davis’ Point: Whole wheat bread has a glycemic index (GI) of 72, which is higher than table sugar (GI = 59).
Jones’ Analysis: One aspect of GI that is frequently misunderstood is that the measure is often used to compare very different amounts of food. Fifty grams of sucrose or glucose (approximately 3 tablespoons) would yield 50 grams of available carbohydrate. Fifty grams of available carbohydrate from whole wheat bread is much more than 50 grams of bread since bread is not all carbohydrate, and all carbohydrate is not available. Thus, it would take 144g of whole wheat bread (5.1 slices at 28g per slice) or 111g of white bread (3.9 slices) to yield 50g of available carbohydrate.
Davis’ Point: Whole wheat bread consumption results in the same blood glucose response as white bread consumption: “Eating 2 slices of whole wheat bread increases blood sugar more than a candy bar.”
Jones’ Analysis: While it is true that whole wheat bread consumption produces the same glucose response as white bread consumption, it takes more whole wheat bread than white bread to obtain the same glucose response. Although it is also correct that whole wheat breads have a higher GI than a candy bar such as a Mars or Snickers bar, as previously mentioned the GI compares 50g of available carbohydrate, which is about 4 slices of whole wheat bread and about 2.5oz of Mars bar, so the volume of food is different. In addition, there are several factors involved in available carbohydrate levels, including the fat content of the food, which impedes amylase activity. Because the calories and nutrients delivered by the two products are so vastly different, it is not possible to make a direct comparison that is meaningful. It should also be pointed out that not all whole wheat breads yield higher GIs.
Davis’ Point: Wheat opioids are so addictive they cause people to be unable to control their eating, and removal of wheat from the diet causes withdrawal.
Jones’ Analysis: The control of eating and the onset of satiety are affected by many mechanisms, from physical feelings of fullness to neuroendocrine, psycho/emotional, social, and sensory factors. Human data on withdrawal effects from foods or their components, except for caffeine, are nonexistent. There is no evidence to substantiate Davis’ claims about withdrawal symptoms resulting from removal of wheat from the diet. In addition, Davis’ claims that wheat causes uncontrollable overeating conflict with existing data, which show release of satiety hormones resulting from the ingestion of wheat. In fact, some data suggest that consumption of proteins such as those in gluten may be a good dietary strategy for weight management.
Davis’ Point: Wheat ingestion alters mood and causes mental “fogginess”.
Jones’ Analysis: There is little data showing that wheat consumption alters mood or mental acuity. In a study with a small number of patients with celiac disease, gluten restriction failed to improve the neurological disability. In contrast, increased serotonin is associated with a sense of well-being and elevates mood. Wheat biscuits added to the diets of malnourished Indian primary school-aged children actually improved cognitive ability.
Davis’ Point: Wheat is the product of genetic research, and today we are eating genetically altered wheat.
Jones’ Analysis: Modern cultivated food plants are the product of thousands of years of plant breeding, and wheat is no exception. Wheat breeding is not, as Davis suggests, a new technology that has occurred since 1940, although efforts such as those by Norman Borlaug and others have resulted in significant advances. In 1970 Borlaug won the Nobel Peace Prize for his wheat and grain breeding programs. Programs such as his produced grains with high yields that grow under a wide variety of conditions and help address world food supply challenges. Despite the implications in the book, these varieties were produced using traditional plant breeding techniques. Currently, there are no commercially available genetically modified wheat varieties sold.
Read the full scientific analysis by Julie Jones, PhD, CNS, LN. http://wholegrainscouncil.org/files/WheatBellyJulieJonesCFW.pdf