Science conflicts with 'Wheat Belly' theory on weight loss
October 18, 2011
by Editorial Staff
SCHAUMBURG, ILL. — Published scientific studies cast doubt on a new book’s premise that says eliminating wheat from the diet may lead to weight loss, said Glenn Gaesser, chairman of the Grain Foods Foundation’s scientific advisory board, on Oct. 2 in Schaumburg.
William Davis wrote the book “Wheat Belly: Lose the Wheat, Lose the Weight, and Find Your Path Back to Health.” Published in September, it attempts to connect wheat to such issues as weight gain, diabetes and heart disease.
“It’s really about carbs — it’s a low-carb diet that he’s advocating,” Dr. Gaesser, a professor and director of the Healthy Lifestyles Research Center and the Exercise and Wellness program at Arizona State University, said while taking part in a Grain Foods Foundation nutritional panel.
Dr. Gaesser, in response to the book, pointed to an article he had published in the October 2007 issue of the Journal of the American Dietetic Association. He wrote reviewing relevant literature indicates that most epidemiologic studies show an inverse relationship between carb-ohydrate intake and body mass index (B.M.I.). The observational studies are supported by results from dietary intervention studies wherein modest reductions in body weight were observed with an ad libitum, low-fat, high-carbohydrate diet without emphasis on energy restriction or weight loss.
Dr. Gaesser also cited a Framingham Heart study concerning belly fat that appeared in the November 2010 issue of The American Journal of Clinical Nutrition. It showed whole grain intake inversely was associated with abdominal subcutaneous adipose (SAT) and visceral adipose tissue (VAT) after adjustment for age, sex, current smoking status, total energy and alcohol intake. In contrast, refined grain intake was associated positively with SAT and VAT in multivariable models.
On June 23 of this year a study of individual foods and weight gain/loss over time appeared in the New England Journal of Medicine. It involved three separate cohorts that included 120,877 women and men who were free of chronic disease and not obese at baseline. Within each four-year period people gained an average of 3.35 lbs. Weight gain most strongly was associated with intake of potato chips (1.69 lbs), potatoes (1.28 lbs), sugar-sweetened beverages (1.00 lbs), unprocessed red meats (0.95 lbs) and processed meats (0.93 lbs). Weight gain inversely was associated with intake of vegetables (minus 0.22 lbs), whole grains (minus 0.37 lbs), fruits (minus 0.49 lbs), nuts (minus 0.57 lbs) and yogurt (minus 0.82 lbs).
“The truth is with us — period — because it is science that is supporting this,” Dr. Gaesser said.
Dr. Gaesser said Dr. Davis in his book connects wheat intake and belly fat through anecdotal evidence.
Dr. Davis in the book writes, “As a cardiologist who sees and treats thousands of patients at risk for heart disease, diabetes and the myriad destructive effects of obesity, I have personally observed protuberant, flop-over-the-belt belly fat vanish when my patients eliminated wheat from their diets, with typical weight loss totaling 20, 30 or 50 lbs just within the first few months. Rapid and effortless weight loss is usually followed by health benefits that continue to amaze me even today after having witness this phenomenon thousands of times.”
References at the end of his book cite studies that examine issues such as how wheat has changed genetically in modern times; whether modern wheat has had an effect on the increasing number of people with celiac disease; and whether celiac disease has led to an increase in such health issues as irritable bowel syndrome and diabetes.
The references include two studies on low-carbohydrate diets that appeared in the May 22, 2003, issue of the New England Journal of Medicine.
One study randomly assigned severely obese patients with a mean B.M.I. of 43 and a high prevalence of diabetes or the metabolic syndrome to a carbohydrate-restricted diet or a low-calorie and fat-restricted diet. A total of 79 people completed the six-month study. The subjects lost more weight during six months on a carbohydrate-restricted diet than on a calorie-restricted and fat-restricted diet with a relative improvement in insulin sensitivity and triglyceride levels.
Another study involved 63 obese men and women. They were assigned randomly to either a low-carbohydrate, high-protein, high-fat diet or a low-calorie, high-carbohydrate, low-fat (conventional) diet. The low-carbohydrate diet produced a greater weight loss than did the conventional diet for the first six months, but the differences were not significant after one year.
Sylvia Melendez-Klinger, a registered dietitian, founder of Hispanic Food Communications and a member of the G.F.F. scientific advisory board, also appeared on the panel as did Shelley Case, a registered dietitian and author of “Gluten-free Diet, A Comprehensive Re-source Guide.”
Ms. Melendez-Klinger said her Mexican clients on average eat 12 corn flour tortillas per meal. They use the tortillas like a fork to shovel in food, she said. She said she promotes the mandatory folic acid fortification of corn flour. The Hispanic population has higher rates of neural tube birth defects, which may be prevented by folic acid consumption, she said.
Ms. Case in her presentation said gluten-free foods may have a positive effect on about 21 million Americans. She said
about 3 million Ameri-cans suffer from celiac disease, which means they must avoid gluten in their diet, and about another 18 million Americans may be gluten-sensitive.
As more is learned about celiac disease, doctors may diagnose more people with it. Ms. Case said one Canadian study showed the delay in diagnosis of celiac disease was about 12 years.