What Is a Specific Carbohydrate Diet?
The Specific Carbohydrate Diet (SCD) is a restrictive, grain-free diet. It is 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 gastrointestinal problems in children with autism.
As the name suggests, the diet allows some carbs and bans others based on how hard they are to digest.
Most support for the Specific Carbohydrate Diet comes from testimonials. A few small clinical studies show that the diet helps 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 a successful treatment and then researched nutrition and gastrointestinal health before writing the book.
How Does the Specific Carbohydrate Diet Work?
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.
Eating only easily digestible carbohydrates can ensure that no undigested carbohydrates are left to feed bad bacteria. This prevents their overgrowth and the chain reaction that leads to irritation.
Specific Carbohydrate Diet vs. Low-FODMAP Diet
Like the Specific Carbohydrate Diet, the low-FODMAP diet is also for people with gastrointestinal problems, such as IBS. It also restricts certain kinds of carbohydrates that you may have trouble digesting. With the low-FODMAP diet, you'll first avoid all high-FODMAP foods, such as specific fruits, vegetables, dairy products, and grains. Then, after a few weeks, you'll slowly reintroduce foods to your diet to see which ones cause symptoms and which don't. People following the SCD may do so for life or reintroduce foods after a year.
Specific Carbohydrate Diet Food List
The book Breaking the Vicious Cycle outlines in detail all the foods that are allowed and not allowed in the SCD:
Foods allowed
- Fresh, unprocessed meat, as well as 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
- Honey
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
- Seaweed
- 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 Science Says
Research supports the Specific Carbohydrate Diet to help treat the inflammatory bowel diseases Crohn’s disease and ulcerative colitis.
Several small studies have shown that SCD can improve symptoms in children with inflammatory bowel disease (IBD), but more research is needed to better understand how effective the diet is.
2017 review of research on the Specific Carbohydrate Diet’s use in treating Crohn’s disease found that the diet shows promise as a nutritional treatment for both adults and children. It also concluded that more research and robust studies are needed before doctors can routinely suggest it.
A 2015 survey of 50 people who followed the diet while in remission from IBD suggested that the diet may be effective in managing the disease for some people. In a 2016 anonymous survey of 417 people with IBD, most said they benefited from the Specific Carbohydrate Diet. But, with self-reported surveys, it’s hard to know exactly what helped them.
Finally, a 2021 comparison of the Specific Carbohydrate Diet with a Mediterranean diet for people with IBD found that both diets led to symptom remission. A Mediterranean diet, however, may be easier to follow.
Starting the Specific Carbohydrate 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 suggests an introductory period of two to five days in which 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 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 suggests staying on the diet until at least one year after the last symptom has disappeared.
Specific Carbohydrate Diet Challenges
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 IBD 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.
Takeaways
The Specific Carbohydrate Diet (SCD) is a restrictive, grain-free eating plan designed to help manage gastrointestinal conditions such as Crohn’s disease, ulcerative colitis, and celiac disease. It allows easily digestible foods like fresh fruits, most vegetables, unprocessed meats, and homemade yogurt while banning grains, starches, processed foods, and lactose-heavy dairy. The diet aims to reduce harmful gut bacteria by removing hard-to-digest carbs. Though testimonials and small studies suggest it may help, more research is needed to confirm its effectiveness and safety.
