The Specific Carbohydrate Diet is a restrictive, grain-free diet plan designed to help people with conditions such as Crohn's disease, ulcerative colitis, celiac disease, diverticulitis, cystic fibrosis, and chronic diarrhea. Some people claim it helps with the gastrointestinal problems that some children with autism have.
As the name suggests, the diet allows some carbs and bans others, based on how hard they are to digest. You can have items including fresh fruit, most vegetables, meat without additives, and homemade yogurt, but not starches, grains, and processed or canned foods.
Most support for the Specific Carbohydrate Diet comes from testimonials. There are a few small clinical studies that show the diet is effective in helping to manage certain gastrointestinal conditions, such as Crohn’s disease and ulcerative colitis. But more research is needed on its safety and effectiveness.
How It Started
Pediatrician Sydney Haas, MD, created the Specific Carbohydrate Diet in the 1920s to treat celiac disease. Elaine Gottschall, a biochemist and the mother of one of Haas’s patients, made the diet more widely known in 1987 when she published Breaking the Vicious Cycle: Intestinal Health through Diet. The book outlines the diet and includes recipes.
According to her book, Gottschall’s young daughter had been diagnosed with severe ulcerative colitis. Gottschall reportedly used the diet as successful treatment and then did further research on nutrition and gastrointestinal health before writing the book.
How the Diet Works
The theory behind the Specific Carbohydrate Diet is that certain carbohydrates are not fully digested, so they remain in the gut and must be broken down by the bacteria there. This can cause an overgrowth of harmful bacteria, and waste products of the digestion process can set off a chain reaction, or “vicious cycle,” of irritation in the intestines.
By limiting your carbohydrates to only ones that are very easily digested, the idea is that there will be no undigested carbohydrates left over to cause overgrowth of bad bacteria and set off the chain reaction leading to irritation.
Here is a general look at which foods are allowed on the diet. Breaking the Vicious Cycle outlines in detail all the foods that are allowed and restricted.
- Fresh, unprocessed meat, poultry, fish, shellfish, and eggs
- Certain legumes, including dried beans, lentils, split peas, raw cashews, and all-natural peanut butter
- Cheeses such as cheddar, Colby, Swiss, and dry curd cottage cheese
- Homemade yogurt fermented for at least 24 hours
- Most vegetables
- Fresh, frozen, or dried fruits with no added sugar
- Most nuts and nut flours
- Most oils, teas, coffee, mustard, cider or white vinegar, and juices with no additives
Foods Not Allowed
- Sugar, molasses, maple syrup, sucrose, processed fructose
- Grains, including corn, wheat, wheat germ, barley, oats, and rice
- Canned vegetables with added ingredients
- Some legumes
- Starchy tubers such as potatoes, sweet potatoes, and turnips
- Canned or processed meats
- Canola oil and store-bought mayonnaise
- All milk and milk products high in lactose, such as mild cheddar, store-bought yogurt, cream, sour cream, and ice cream
- Candy and chocolate
What the Research Says
There is a small but growing body of research that supports the Specific Carbohydrate Diet to help treat the inflammatory bowel diseases Crohn’s disease and ulcerative colitis.
Several small studies have shown that it can improve symptoms in children with inflammatory bowel disease. The studies all note that more research is needed to get a better understanding of how effective the diet is.
A 2017 review of research on the Specific Carbohydrate Diet’s use in treating Crohn’s disease concluded that the diet shows promise as a nutritional treatment for both adults and children. It also concluded that more research and stronger studies are needed before doctors can routinely recommend it.
A 2015 survey of 50 people who followed the diet while in remission from inflammatory bowel disease suggested that the diet may be an effective tool in managing the disease for some people. In a 2016 anonymous survey of 417 people with inflammatory bowel disease, most people said they benefited from following the Specific Carbohydrate Diet. But it’s hard to know with self-reported surveys exactly what helped them.
Starting the Diet
Talk to your doctor before you begin the Specific Carbohydrate Diet to make sure you’ll get the calories and nutrients you need.
Gottschall’s book, Breaking the Vicious Cycle, recommends an introductory period of 2 to 5 days where you only eat a few specific foods. Then, you slowly add items in stages.
It’s a good idea to keep a food journal while you’re on the diet. Write down what you eat each day and how you feel. This will help you track your progress and spot connections between foods and symptoms.
Some people whose symptoms completely stop after following the diet may be able to gradually come off the diet without becoming sick again. But others may have to remain on the diet indefinitely. In her book, Gottschall recommends remaining on the diet until at least 1 year after the last symptom has disappeared.
People on the Specific Carbohydrate Diet may not get enough of certain nutrients, including folate, thiamine, vitamin B6, calcium, and vitamin D. A study looking at nine children using the diet to treat inflammatory bowel disease found that they didn’t get enough vitamin D and calcium.
Because it eliminates processed foods and limits a lot of other foods, it can be hard to stick to this plan. A study of 50 people on the diet found the average person spent nearly 11 hours a week preparing food. The diet may also make it harder for you to eat enough calories to maintain a healthy weight.