What Is the Specific Carbohydrate Diet (SCD)?
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Medically reviewed by Barbie Cervoni, RD
The specific carbohydrate diet (SCD) is an exclusion diet that’s used to treat certain health conditions, such as inflammatory bowel disease (IBD). When following the SCD, people cut out many foods, including grains, starches, some dairy products, and added sugars.
Research shows the SCD can be effective for reducing symptoms and inducing remission in people with IBD, but the diet comes with a few downsides.
Here’s everything you need to know about the SCD, including how it works, who it may benefit, foods to eat and avoid, and drawbacks to consider.
How the Specific Carbohydrate Diet Works
The SCD was developed by pediatrician Dr. Sidney Haas in the 1920’s as a treatment for celiac disease. A different version of the diet became a popular treatment for IBD after the publication of the book Breaking the Vicious Cycle: Intestinal Health Through Diet, by Elaine Gottschall in 1994. Gottschall wrote the book after her daughter’s ulcerative colitis (UC) was cured by her following the SCD.
The SCD is based on a theory that IBD is associated with dysbiosis, a medical term used to describe an imbalanced microbiome (the microbes that reside in the digestive system). The goal of the SCD is to eliminate foods, beverages, and ingredients that may contribute to dysbiosis and replace them with foods known to support the growth of beneficial bacteria, rebalance the microbiome, improve nutrient absorption, and strengthen and restore the gut.
This improvement in the health and composition of the gut microbiome reduces inflammation and IBD symptoms and may even help some people achieve remission.
The foods allowed on the SCD are based on their carbohydrate structure. Only specific types of carbs are allowed on the diet, hence the name. Foods allowed on the SCD are mostly composed of monosaccharides, which are simple carbohydrates. Your body breaks down all carbohydrates into monosaccharides, which are the simplest and smallest type of sugar made of just one sugar unit.
Monosaccharides are absorbed into the bloodstream so they can be used for energy. When following the SCD, foods that contain disaccharides, polysaccharides, and starches are eliminated, as these more complex carbohydrates are harder to digest and may contribute to intestinal inflammation.
The SCD is usually used as a temporary diet, and most people start reintroducing foods into their diet after months or years of following the SCD.
However, some people follow the SCD for life to control IBD symptoms or remain in remission.
Guidelines of the Specific Carbohydrate Diet
Before beginning the SCD, it’s recommended that people who are experiencing severe symptoms, such as severe cramping and diarrhea, follow an introductory diet for two to five days before moving on to the SCD. During the introduction period, food intake is limited to just a few, easily digested foods.
On her website, Gottschall provides a meal plan for the introductory period that consists of dry curd cottage cheese, eggs, diluted apple cider and grape juice, homemade gelatin, homemade chicken noodle soup, homemade SCD-friendly cheesecake, and broiled beef and fish.
After completing two to five days of the introduction diet, you can start introducing SCD “legal” foods. There is no specified schedule for introducing SCD-legal foods, but there are certain guidelines that should be followed, including:
Ripe fruits and vegetables should initially be peeled and cooked thoroughly.
Most raw fruits and vegetables should not be introduced to the diet until diarrhea has subsided or is under control. Very ripe bananas with brown spots are the one exception to this rule.
Slowly introduce new foods based on your symptoms.
If foods seem to trigger or worsen symptoms such as gas or diarrhea when they are introduced, these foods should be removed and then reintroduced at a later time.
SCD-legal foods that have caused symptoms in the past should be removed from the diet if they continue to cause symptoms after a week of elimination.
Foods that contain carbohydrates other than those found in SCD-legal foods, such as fruits, honey, and SCD yogurt, are strictly forbidden.
Gottschall’s book, Breaking the Vicious Cycle: Intestinal Health Through Diet, provides more detailed information about the SCD guidelines and provides recipes for SCD yogurt, chicken noodle soup, and more.
What to Eat on the Specific Carbohydrate Diet
The SCD is composed of foods that are easy to digest, nutrient-dense, and unlikely to exacerbate symptoms related to IBD, like diarrhea and bloating.
The goal of the SCD is to prioritize foods that may help promote gut health, rebalance gut bacteria, and reduce IBD symptoms. People following the SCD consume minimally processed foods such as fruits, vegetables, and protein sources like fish.
When following the SCD, you can eat the following SCD-legal foods:
Protein: Meats without additives, poultry, fish, shellfish, and eggs
Certain legumes: Dried navy beans, lentils, peas, and split peas
Certain nuts, seeds, and nut flours: Unroasted cashews, almonds, seed butters, natural peanut butter, almond flour, and almond butter
Limited dairy products: Aged cheeses such as cheddar, blue cheese, and Swiss, dry curd cottage cheese, and homemade SCD yogurt fermented for at least 24 hours
Most vegetables: Beets, broccoli, asparagus, spinach, and more
Most fruits: Apples, strawberries, bananas, pineapple, and more
Most fats: Olive oil, avocados, coconut, butter, coconut oil, and more
Sweeteners: Honey and saccharin
Other foods and beverages: Apple cider, tea, vodka, coffee, apple cider vinegar, mustard, and balsamic vinegar
Keep in mind the list of SCD-legal foods is extensive, and there are some exceptions to the categories above. For example, Jerusalem artichokes are considered SCD-illegal because they’re a tuber vegetable, while French artichokes are legal. For this reason, people who are interested in the SCD are encouraged to download the complete list of SCD-legal and illegal foods.
Foods Not In the Specific Carbohydrate Diet
When following the SCD, many foods are off-limits. Grains and starches of all kinds are restricted, which can make this diet challenging to follow.
When following the SCD, you’ll need to avoid:
Most sweeteners: Sugar, maple syrup, corn syrup, molasses, and more
Foods and drinks with added sugars: Soda, sweetened juices, chocolate, candy, sweetened coffee drinks, and more
All grains: Rice, amaranth, wheat flour, corn, barley, oats, pasta, and more
All tuber vegetables: Potatoes, sweet potatoes, Jerusalem artichokes, and more
Some dairy products: Milk, ice cream, sour cream, buttermilk, and more
Seaweed: Seaweed chips and other seaweed products
Some legumes: Black-eyed beans, butter beans, cannellini beans, fava beans, and more
Most alcoholic beverages: Beer, wine, sugary mixed drinks, and more
The list of SCD-illegal foods is extensive, and people who want to learn more about foods that are restricted on this diet should refer to the complete list on Gottschall’s website.
Meal Ideas for the Specific Carbohydrate Diet
When following the SCD, meals must be made with SCD-legal foods and be free from SCD-illegal foods and ingredients.
A day of eating on the SCD may look like:
Breakfast: Omelet made with eggs, cheddar cheese, and spinach served with berries and sliced avocado
Lunch: Chicken and vegetable soup with grain-free lentil-based noodles
Snack: Homemade SCD yogurt topped with sliced bananas, chopped almonds, and honey
Dinner: Grilled fish served with asparagus and roasted carrots
There are several websites that share SCD-friendly meal and snack ideas, which makes it easier to find ways to create tasty and nutritious recipes when following the SCD.
Benefits of the Specific Carbohydrate Diet
The SCD has been shown to reduce symptoms for people with certain digestive disorders, including Crohn’s disease and ulcerative colitis.
May Reduce Symptoms of Inflammatory Bowel Disease
The most evidence-based benefit of the SCD is its ability to improve symptoms related to IBD in both children and adults. In some studies, children and adults who followed the SCD attained remission, which is defined as the resolution of active IBD symptoms or the absence of active disease or inflammation.
Though there’s a lack of large-scale studies, some research suggests the SCD can help decrease inflammation, improve symptoms like diarrhea, and heal the gut lining in children and adults with IBD.
A small study that included 18 children with Crohn’s disease found that the children who were randomized to an SCD for 12 weeks had significant decreases in the inflammatory marker C-reactive protein and achieved clinical remission at week 12. The study found that while less restrictive diets, including a version of the SCD that allowed some grains, had a positive effect on symptoms and inflammation, the SCD was associated with a greater reduction in inflammation.
In another study that included survey information from 417 people with ulcerative colitis (a type of inflammatory bowel disease), 33% of the participants reported remission at two months after starting the SCD, and 42% reported achieving remission at both six and 12 months. This suggests that the SCD can be effective for helping people with IBD gain control of their symptoms and may help some people achieve remission.
Other studies have also reported the SCD helps reduce IBD symptoms and may help people attain remission in some cases.
However, it’s currently unclear if the SCD is more effective than other, less restrictive diets for IBD. A study that included 191 adults with Crohn’s disease who were randomized to follow an SCD or a Mediterranean diet for 12 weeks found that the SCD was not superior to the Mediterranean diet in terms of symptom remission and markers of disease and inflammation.
Though some evidence suggests the SCD could be a worthwhile diet for those with IBD, more research is needed.
Might Improve Some Neurological Diseases
Though research is currently limited, some evidence suggests the SCD may be helpful for certain neurological disorders, such as autism spectrum disorder (ASD).
A case study reported that four months of following the SCD led to improvements in nutrient status, gastrointestinal symptoms, and behavioral issues in a four-year-old boy with ASD and Fragile X Syndrome (FXS), a genetic disorder that causes intellectual disability.
The theory behind using the SCD stems from research findings indicating that dysbiosis and impaired carbohydrate digestion might contribute to behavioral issues and GI symptoms in those with ASD.
However, there’s currently not enough evidence to support recommending the SCD as a way to treat any neurological disease, including ASD, especially in children who are more sensitive to restrictive diets.
Safety and Drawbacks of the Specific Carbohydrate Diet
The SCD is generally considered safe and nutritionally complete if followed appropriately.
However, it’s highly restrictive, which can lead to issues in certain populations. For example, though this diet is used in pediatric populations, there are high dropout rates in studies investigating the effects of the SCD in kids. This suggests that this diet may be difficult for children to follow.
Adults may also have a hard time following the SCD for a long period of time as the diet cuts out so many foods and ingredients that commonly make up large percentages of most diets.
In addition to its restrictiveness, the SCD can be challenging to execute and follow. A study that included 208 patients and caregivers utilizing the SCD identified barriers when using the SCD, such as a steep learning curve, significant time commitment, and a lack of support from healthcare professionals.
Because the SCD is so restrictive and involves extensive legal and illegal food lists, specialized recipes, and other rules, it’s suggested to work with a healthcare provider experienced in the SCD if you’re interested in trying it out.
A Quick Review
The specific carbohydrate diet (SCD) is a dietary protocol that restricts specific types of carbohydrates, such as grains and tubers, and prioritizes foods that promote gut health.
Some research suggests that the SCD may help improve symptoms and disease markers in people with inflammatory bowel disease and may help some people attain remission.
However, the diet is very restrictive and may be hard to follow, especially long-term. If you’re interested in following the SCD, it’s recommended to work with a healthcare provider who has extensive knowledge of the SCD to ensure you’re following the diet in a safe and appropriate way.
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