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Gluten-free Diets Are Harmful for the General Population (Except for one percent)

Updated November 11, 2021

By John McDougall, MD

The current gluten-free diet craze is unhealthy for those who do not need it—those without celiac disease. In search of weight loss and/or feeling better, millions of Americans risk becoming sicker and fatter by increasing their intake of gluten-free products. Estimates are as high as 15 to 25 percent of consumers in the US want gluten-free food, with the global market of gluten-free products approaching $2.6 billion in 2010. 

Three Potential Problems from Wheat

Celiac Disease:

Celiac disease results from damage to the intestines caused by eating gluten, found in wheat, barley, and rye, in genetically susceptible people. The resulting malabsorption prevents the small intestine from efficiently absorbing necessary nutrients. Diarrhea, abdominal pain, flatulence, weakness, and weight loss are frequent. Gluten damage to the intestinal barrier creates a “leaky gut.” Now “foreign proteins” from microbes and food are indiscriminately allowed to pass through the intestinal wall, causing all kinds of trouble. People with untreated celiac disease have a two to six times greater risk of dying, mainly due to an increase in the risk of lymphoma, and a much greater risk of suffering from autoimmune diseases, such as type-1 diabetes and thyroiditis (leading to hypothyroidism).

The definitive diagnosis of celiac disease is made by a bowel biopsy showing damage to the intestinal lining (villous atrophy). Blood tests (endomysial and tissue transglutaminase antibodies) help support the diagnosis. The cornerstone of treatment is lifelong adherence to a strictly gluten-free diet.  

Wheat Allergies:

Wheat allergies are classically found as two conditions: baker’s asthma and rhinitis (runny nose). However, allergies to components of wheat may cause, and contribute to, many other problems, including inflammatory arthritis.

Wheat Sensitivity:

A new category of problems classified as “wheat sensitivity” or “non-celiac gluten intolerance” has recently become widely recognized. This form of gluten intolerance is diagnosed when both celiac disease and wheat allergy have been excluded. Symptoms include abdominal discomfort, bloating, pain, and diarrhea. In addition, many people relate headaches, “foggy mind,” depression, fatigue, muscle cramps, joint pain, numbness, and skin rash to wheat sensitivity. The actual incidence of non-celiac gluten intolerance is unknown. 

Because this condition is so non-specific, my guess is that most of these people are simply sick from their unhealthful diet of meat, dairy foods, vegetable oils, and other junk food. Blaming gluten or wheat is wrong, and as a result, their efforts on gluten-free eating are misplaced. Benefits seen while attempting any new more restrictive diet regimen are from simply removing foods recognized to be unhealthful, irrelevant to their containing gluten or not.

Gluten-free Can Be a Disguise for Low-carb Eating

The national best-selling book, Wheat Belly, by William Davis, MD, has fueled the current rage for gluten-free foods. The book’s subtitle is “Lose the wheat, lose the weight, and find your path back to health.” Misquoting the research and ignoring the bulk of the scientific evidence, Dr. Davis has convinced people, as well known as Fox News TV co-host Bill O’Rielly, that avoiding wheat is the solution to America’s obesity and health crises. Dr. Davis says “modern wheat is a perfect chronic poison; it causes diabetes, it causes inflammation, it causes heart disease, it causes high blood pressure….” He goes on to claim in a CBS News interview that the elimination of wheat will cure these conditions and cause people to stop their medications.

Although I applaud Dr. Davis for bringing problems with wheat to greater public awareness, I consider this fad a serious diversion away from what I believe to be the real solution to obesity and common diseases: a starch-based diet. Traditionally my kind of high-carbohydrate eating has been the diet of people throughout recordable human history, and a large share of these civilizations, ancient and modern, have relied on generous amounts of wheat, barley, and/or rye for survival.

While exaggerating the benefits of a wheat-free diet, Dr. Davis makes clear his alliance with the low-carb movement, typified by the popular Paleo and Atkins diets. He recommends people eat unlimited amounts of eggs, full-fat cheese, other dairy products, meat, fish, chicken, and vegetable (olive) oils; and reducing or eliminating favorite (even non-gluten) “comfort foods,” like corn, rice, oats, quinoa, millet, buckwheat, potatoes, and beans. My opposite conclusion is that Dr. Davis’s prescription for filling the dinner table with rich foods, those once reserved for the tables of opulent kings and queens, is actually the cause of the current epidemics of obesity and common illnesses in the developed world, not the solution. 

The AACC International (formerly the American Association of Cereal Chemists), a global nonprofit organization of 2,500 grain scientists and professionals studying the chemistry of cereal grains and their products, also disagrees with Dr. Davis and has responded with a scientific analysis of a few of his claims.

Gluten-free Diets Cause Weight Gain

Patients with celiac disease are usually suffering with malnourishment because of the problems created by damage to their intestines from gluten. Following removal of the wheat, barley, and rye, the GI track usually heals, and only then are calories and other nutrients efficiently assimilated. Weight gain is the desired and expected result for underweight people with celiac disease. Some people with documented celiac disease, however, are overweight, and even obese, before starting a gluten-free diet. You might expect that the dietary restrictions imposed by a strict gluten-free protocol alone would cause weight loss for them. Unfortunately, weight gain is a common occurrence in overweight and obese adults and children with celiac disease who go on gluten-free diets. A 2012 study of 1018 patients with biopsy confirmed celiac disease found significant weight gain; with 16 percent of patients moving from a normal or low BMI (body mass index) class into an overweight BMI class, and 22 percent of the patients who were overweight at the time of diagnosis gaining weight after starting their strict gluten-free diet.

Let me be more to the point for the growing masses looking for the answer: “There are no published reports showing that a gluten-free diet produces weight loss in persons without celiac disease or gluten sensitivity.” To reiterate this point, a 2011 article in the Journal of the American Dietetic Association states, “At this time there is no scientific evidence supporting the alleged benefit that a gluten-free diet will promote weight loss.”

The primary reason for unwanted weight gain found in people buying gluten-free products is that these imitations often contain more calories, fat, and sugar, and fewer important nutrients (dietary fiber, complex carbohydrates, vitamins, and minerals) than the original gluten-containing foods. Even the casual observer can see the folly in eating gluten-free cakes, cookies, and pies, and expecting weight loss and better health. A trip through your local health food store or supermarket reveals rows of desserts where the wheat has been replaced with another grain (flour); and fats, vegetable oils, simple sugars, dairy products, and eggs are abundant on the ingredient lists.

Percent of Fat Calories from Popular Gluten-free Foods

Falafel 71%
Cheese Pizza 36%
Brownies 38%
Cupcakes 37%
Chocolate Cake 38%
Chocolate Chip Cookies 50%

These foods also can contain saturated fats, free vegetable oils, simple sugars, refined flours, nuts, soy, dairy products, and eggs.

When an expert dietitian, knowledgeable about proper food choices for a healthy gluten-free diet, devoid of cakes, cookies, and pies, is involved in patient care, then weight loss is accomplished. In one study overweight and obese patients were advised to choose a high quality gluten-free diet with naturally gluten-free foods (fruits and vegetables) and alternate non-gluten containing grains (quinoa and buckwheat). These properly counseled patients consistently lost excess weight. There is unfortunately a paucity of dietitians and medical doctors available for the proper management of celiac disease.

This Fad Ultimately Harms Many Celiac Patients

If you are one of the few people with celiac disease, then avoiding gluten is crucial to your health. You cannot cheat! With the popularity of “going gluten-free,” for unsubstantiated reasons, the importance of this dietary restriction for the truly needy has been diminished. Waiters at restaurants become used to customers asking for “gluten-free dishes” and then failing to object when a few whole wheat bread crumbs appear as a decoration on top of their potato soup. Since wheat, barley, and rye did not cause any apparent distress in the previous 99 customers, the waiters and chefs think, “It can’t be all that important.” But it is for that one percent.

Dr. McDougall’s Recommendations:

If you suspect that you have celiac disease, get tested by your physician. Avoidance of gluten foods is a lifelong restriction. If you are unsure about your diagnosis, but still suspect gluten, then go on a starch-based diet, with no wheat, barley or rye. For example, you can base your diet on rice, corn, sweet potatoes, white potatoes, and beans, with fruits and green and yellow vegetables. The connection between gluten and celiac disease is so close that the diagnosis can often be made when the patient experiences dramatic improvement of symptoms upon following a gluten-free diet. Confirmation of your diagnosis can be made by carefully adding back any suspected foods. 

If you, like two-thirds of adults in the US, are sick and overweight, and of the vast majority whom are also without celiac disease, wheat allergy or wheat sensitivity, then I strongly recommend that you include these good starches—wheat, barley and rye—in your diet because these foods are known to cause desirable weight loss and medical benefits.

McDougall Foods Acceptable for Celiac Disease



Buckwheat (or kasha)


Job’s tears






Wild rice 


Other Foods:

All root vegetables, like potatoes, yams, sweet potatoes, and cassava-root (tapioca)

All legumes**, more specifically, beans (including soy and chickpeas), peas and lentils

All green, yellow, and orange vegetables

All fruits

* Oats have been demonstrated in multiple studies to be free of toxic proteins and can be tolerated by most, but not all, people with celiac disease; but there is worry that commercial oat products may be contaminated with wheat. 

**Legumes create extra gas, sometimes causing bloating and bowel discomfort. This reaction may be confused with symptoms of celiac disease and wheat sensitivity.