What to Know About the Specific Carbohydrate Diet (SCD)

The specific carbohydrate diet (SCD) is an eating plan that restricts complex carbohydrates. It was first developed many decades ago for the management of celiac disease. However, it is now being considered and studied for use in other conditions, such as Crohn’s disease and ulcerative colitis (two types of inflammatory bowel disease, or IBD).

This article will give a broad overview of the specific carbohydrate diet and show some of the studies that have looked at its use for certain diseases and conditions. 

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How the Specific Carbohydrate Diet (SCD) Started

The SCD was created by pediatricians to treat celiac disease. It was outlined in The Management of Celiac Disease, written by father-and-son medical doctors (M.D.s), Sidney Valentine Haas and Merrill P. Haas.

The elder Haas noted certain carbohydrates than others were better tolerated by his patients with celiac disease. He went on to develop the SCD as a treatment. 

In celiac disease, a protein found in wheat, barley, and rye (called gluten) causes the body to attack the lining of the small intestine. The treatment is avoiding foods that contain gluten. Gluten-containing foods are eliminated on the SCD, and an initial study showed it helped with symptoms of celiac disease.

The eating plan became more popular in the 1990s when Elaine Gottschall popularized it. Gottschall was searching for a treatment for her daughter, who lived with severe ulcerative colitis. She worked with Sidney Haas to use his SCD plan as a treatment.

Gottschall's daughter improved on the diet. Gottschall went on to earn degrees in biochemistry and cell biology and continued to study the SCD. She had little support but was able to self-publish her book outlining the SCD, Breaking the Vicious Cycle: Intestinal Health Through Diet, in 1994.

How the Specific Carbohydrate Diet Works

The theory behind the SCD is to eliminate complex carbohydrates from the diet. However, simple carbohydrates are still allowed.

The digestive system contains many different types of bacteria (which are part of the gut microbiome). Keeping them in balance is important because some types can cause symptoms if they grow too numerous.

The theory of the SCD is that complex carbohydrates become food for potentially harmful bacteria. Therefore, avoiding certain carbohydrates may starve the harmful bacteria and allow beneficial types to flourish.

Other food types avoided on the SCD include processed foods, food additives, preservatives, and sugar. Some of these types of foods have been shown to contribute to inflammation. It’s thought that avoiding these foods might also help with symptoms within the digestive tract. Simple carbohydrates, which are easier to digest, are allowed on the SCD.

The SCD is an eating plan with several progressive steps leading to a maintenance phase. It is meant to be used long-term to control symptoms. In some cases, people may introduce certain disallowed foods back into their diet on a limited basis upon reaching a year without symptoms.

What to Eat

The SCD diet categorizes foods as "legal" (allowed) and "illegal" (not allowed). It is not always apparent into which list individual foods fall, so following the plan means consulting the master list.

In general, the following foods are included in the SCD:

  • 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
  • Fresh or frozen vegetables
  • Fresh, frozen, or dried fruits with no added sugar
  • Fresh, unprocessed meat, poultry, fish, shellfish, and eggs
  • Homemade yogurt fermented for at least 24 hours
  • Honey
  • Most nuts and nut flours
  • Most oils, teas, coffee, mustard, cider or white vinegar, and juices with no additives

Foods to Avoid

Foods to avoid, in general, include those that contain complex carbohydrates, additives, or sugar. Avoiding certain other foods, such as the following, when first starting the diet or when symptoms are active may also be recommended:

  • All milk and milk products high in lactose (a milk sugar), such as mild cheddar, store-bought yogurt, cream, sour cream, and ice cream
  • Canned vegetables with added ingredients
  • Canned or processed meats
  • Canola oil and store-bought mayonnaise
  • Candy and chocolate
  • Grains, including corn, wheat, wheat germ, barley, oats, and rice
  • Preservatives 
  • Seaweed
  • Some legumes
  • Starchy tubers such as potatoes, sweet potatoes, and turnips
  • Sugar, molasses, maple syrup, sucrose, processed fructose

How to Start the Specific Carbohydrate Diet

Before starting a new eating plan, discussing it with a healthcare professional, such as a registered dietitian, is important. A diet that is too restrictive could lead to a lack of nutrients. A healthcare provider can give direction to avoid malnutrition.

Starting the SCD begins with an introductory diet. This diet is followed for two to five days, depending on when symptoms begin to improve. 

The introductory diet is restrictive. To follow it to the letter, it’s necessary to make the foods at home with specific ingredients, as outlined in Breaking the Vicious Cycle: Intestinal Health Through Diet

For informational purposes only, here is a broad outline of foods included in the various stages.

The plan begins with an introductory period of two to five days. Foods included are:

  • Dry curd cottage cheese
  • Eggs (boiled, poached, or scrambled)
  • Pressed apple cider or grape juice (mixed half and half with water)
  • Homemade gelatin made with unsweetened juice, unflavored gelatin, and sweetener (honey or an artificial sweetener)
  • Homemade chicken soup
  • Broiled beef patty or broiled fish
  • SCD cheesecake

The next step is stage 1, which includes all the foods in the introductory diet plus:

  • Peeled, seeded, well-cooked vegetables 
  • Fruits such as ripe banana, applesauce, peeled/seeded and well-cooked pear sauce
  • Meat
  • Alternative milks, such as homemade coconut, almond, or pecan milk
  • SCD yogurt

Stage 2 includes all the above plus nut butter and fruits such as apricot, avocado, peaches, pineapple, and plums.

Stage 3 includes all of the above plus dried fruit and raisins with no added sugars and meats, including fried pork or SCD-legal bacon.

Stage 4 includes all of the above plus raw vegetables, peeled and seeded fruits including raw, nut and seed flour, small portions of nuts and shredded coconut, and legumes (soaked and well-cooked split peas, lentils, navy, and lima beans).

Stage 5 is the maintenance phase that includes all the foods on the allowed list.

What Conditions Can the SCD Help With?

Diet is notoriously difficult to study. This is for many reasons, including that eating plans are personal and dependent on factors such as income, time and effort needed to cook meals, food preferences, and cultural or religious practices. There are still not a lot of trials on eating plans as a treatment for various diseases and disorders. 

Proponents of the SCD recommend it for autism, Crohn’s disease, ulcerative colitis, diverticulitis, celiac disease, cystic fibrosis, and other forms of chronic diarrhea (such as irritable bowel syndrome or IBS). However, there’s not any study to support the use of the eating plan for diverticulitis, celiac disease, cystic fibrosis, or other chronic diseases.

Another diet that is often recommended for general health and for people living with chronic conditions is the Mediterranean diet. One study showed that for Crohn’s disease, SCD was not better than the Mediterranean diet when it came to treating mild to moderate Crohn’s disease. However, the Mediterranean diet is less restrictive than the SCD. 

Another small study showed a change in the C-reactive protein (CRP) blood marker for pediatric participants who followed the SCD diet, a modified SCD diet, or a whole foods diet. A higher CRP level can indicate more active disease. The 10 children in this study who followed the diet had lowered CRP levels at the end of the 12-week study.

However, the European Society for Clinical Nutrition does not recommend the SCD (or any other specific eating plan) for use in treating any form of IBD.

There is currently little data to support the use of the SCD for autism in children. One study showed that autistic children did well on the diet and had improved gut symptoms. But there is a need for more evidence. There is also a concern that the SCD is restrictive and could lead to nutrient deficiencies in children.

One study compared the low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet to the SCD for people with IBS. The 73 participants in the study were randomized to one of these eating plans. Patients in the low-FODMAP diet had less bloating and distention and improved symptoms, while the SCD didn’t seem to provide any benefits.

Professional Opinions on the SCD

The SCD is not endorsed by either patient advocacy groups or professional medical societies for the treatment or management of inflammatory bowel disease (IBD).

SCD Challenges and Risks

The SCD may also be associated with some challenges for those looking to try it or use it for long-term management. For that reason, it’s important to engage the help of a healthcare provider when trying a restrictive eating plan.

It’s also important to note that these challenges are not only found when following the SCD. While the low-FODMAP diet is considered less restrictive, it is similar enough to the SCD that it may also have the same challenges. However, the low-FODMAP diet is typically recommended only for IBS.

Cost

Adhering to the diet may mean an increase in food costs. Some of the disallowed foods tend to be less expensive than allowed foods. Strictly following the allowed foods may increase the grocery bill for some people.

Time

There is a time component to understanding and implementing the SCD. Some foods will need to be created at home from fresh ingredients. Plus, understanding the list of allowed foods and consulting it will take effort, especially in the beginning. One study showed that people spent about 11 hours preparing food each week.

Traveling or Dining Out

Finding SCD legal foods may be challenging when traveling or when socializing. Some people may need to rely on bringing their own foods or snacks with them or eating before going out.

Weight Loss

Limiting carbohydrates may cause weight loss in some people. This effect might not be helpful for people living with a chronic condition such as IBD that may already cause weight loss. Some people may find it challenging to get enough calories because they can’t eat enough allowed foods to meet their needs.

For children living with IBD, one retrospective study showed that kids following the SCD who achieved remission usually increased their weight to the standard range. However, a few children in the study had concerning weight loss.

Nutritional Deficiencies or Malnutrition

The SCD is considered a low carbohydrate diet. These types of diets can be low in thiamine, folate, vitamin C, magnesium, iron, vitamin D, vitamin E, vitamin B7 (biotin), fiber, and calcium. One study on the SCD in children with IBD showed that kids on the eating plan did not get enough vitamin B1, vitamin D, or calcium.

Should You Try the SCD?

Whether you want to give the SCD a try depends upon several factors.

Discuss it with a healthcare provider to determine if it's appropriate for you or your child. Sometimes, a healthcare provider may think it is unlikely to be harmful. But for people who are seriously ill or underweight, there may be concerns about using a restrictive eating plan until their disease is better controlled.

Other considerations include having the time to devote to understanding the SCD and preparing food, having access to allowed foods, and being able to incorporate the eating plan into your lifestyle.

Diet is an important part of the quality of life. How, when, where and with whom you share meals is a part of life that can be associated with comfort and companionship. This is also worth taking into consideration when deciding to try the SCD.

Summary

The SCD is an eating plan that has been in use for many decades as a treatment for digestive symptoms. Despite it being widely used, especially in IBD, there is little evidence yet to show that it is beneficial in treating the condition.

Potential drawbacks to using the SCD, include getting enough calories, vitamins, and minerals. However, there may be benefits. Most people won’t know if SCD will help them until they try the plan and engage the help of a healthcare provider to follow it carefully.  

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.