"The gluten-free diet helps people whose bodies cannot tolerate gluten, a protein found in wheat, barley, and rye. It is prescribed for patients with gluten intolerance and celiac disease, an autoimmune disorder with a genetic link. People with celiac disease cannot consume gluten products without damaging their intestinal lining. Following a gluten-free diet requires finding replacements for bread, cereal, pasta, and other foods while emphasizing fresh fruits, vegetables, and foods without gluten. However, the gluten-free trend has become a fad for some people without gluten intolerance. Celiac disease is found in only about 1 percent of the population, so a gluten-free diet should be followed only with a physician’s recommendation. Benefits may include reducing symptoms such as chronic diarrhea, cramping, constipation, and bloating, promoting healing of the small intestines, preventing malnutrition, and possibly supporting weight loss. Possible concerns include folate and iron deficiencies, expensive or difficult-to-find gluten-free products, and the need for constant vigilance and careful food-label reading. Low-carb diets, including the Atkins Diet and the South Beach Diet, limit carbohydrates such as grains, fruit, and starchy vegetables to promote weight loss. The theory is that limiting carbohydrates generally lowers insulin levels, causing the body to burn stored fat instead. Some studies have shown that people who followed certain low-carb plans for two years lost an average of nearly 9 pounds, similar to the amount lost on higher-carbohydrate diets. Benefits include an emphasis on whole, unprocessed foods and a reduction in refined carbohydrates such as white flour, white bread, and white sugar. Downsides include the possibility that the first two weeks may allow only 20 grams of carbohydrates per day, which can be dangerously low; higher saturated-fat consumption; higher energy intake; and the unsupported notion that calories do not count. Low-carb diets are not entirely evidence-based and may temporarily improve blood sugar or cholesterol levels while increasing fat and protein consumption."