Trend of three different diets (low carbohydrate diet, fat-free diet, and gluten-free diet), in the USA during the period 2004 to 2011. For the American general population, adopting a gluten-free diet is becoming an increasingly popular option. The market for gluten-free food and beverage products grew at a compound annual growth rate of 28% from 2004 to 2011, eclipsing the low carbohydrate diet and the fat-free diet in 2008, to finish with almost $1.6 billion in retail sales in 2010. By 2012 the market is expected to reach about $2.6 billion in sales. The fact that approximately three million Americans suffer from celiac disease and only a fraction of these patients have been diagnosed implies that patients suffering other forms of proven gluten reaction, including gluten sensitivity and wheat allergy, contribute to this market growth. The rest of the market is filled either by people who undertake the diet as occasional consumers (no medical necessity) or by individuals affected by maladies that have been claimed to be affected by gluten exposure, including autism spectrum disorder, attention deficit hyperactivity disorder, multiple sclerosis and irritable bowel syndrome, but for which there is no evidence of the effectiveness of the diet.