The specific carbohydrate diet (SCD) is popular among people with inflammatory bowel disease (IBD). It focuses on simple carbohydrates and unprocessed foods.

In the 1920s, gastroenterologist Dr. Sidney Haas developed the SCD while focusing on treatments for celiac disease. The diet gained popularity when biochemist Elaine Gottschall published Breaking the vicious cycle: Intestinal health through diet in 1994.

Haas and Gottschall claimed the diet could change the gut microbiome.

The SCD involves eating carbohydrates that are easy to digest and avoiding those that are difficult to digest. Although the diet’s strict nature makes it hard to stick to, some evidence suggests it may help reduce symptoms of intestinal distress.

Read on to learn about the SCD, allowed and restricted foods, potential benefits and risks, and more.

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The SCD is popular among people with inflammatory bowel disease (IBD).

IBD refers to conditions that cause chronic inflammation of the digestive tract. The two main types of IBD are ulcerative colitis (UC) and Crohn’s disease. UC occurs when inflammation affects the colon and rectum. With Crohn’s disease, inflammation occurs anywhere in the gastrointestinal tract, from the mouth to the anus.

The SCD focuses primarily on the type of carbohydrates a person eats.

It allows carbohydrates that are easy to digest. These are monosaccharide carbohydrates, which are made of a single molecule and do not require an enzyme to break them down. They are easy to absorb and digest.

Complex carbohydrates are restricted. Because they are harder to digest, some scientists believe they promote intestinal inflammation.

Harder to digest (complex) carbohydrates include disaccharides, which contain two monosaccharides, and most polysaccharides, which contain a number of monosaccharides.

Learn more about the difference between simple and complex carbs.

The SCD focuses on easily digested carbohydrates and whole, unprocessed foods. Allowed foods include:

  • all fruits
  • nuts and nut flours
  • most non-starchy vegetables
  • most dried beans
  • most seeds
  • non-processed meat and fish
  • eggs
  • dry-curd cottage cheese
  • aged cheeses
  • homemade 24-hour fermented yogurt
  • olive and coconut oils
  • unflavored gelatin
  • honey

The diet restricts carbs that are more difficult to digest, as well as many processed foods. Excluded foods include:

  • all grains
  • corn
  • potatoes
  • soft cheeses
  • milk and cream
  • canned beans
  • all sugar
  • chia, flax, and hemp seeds
  • most artificial sweeteners
  • preservatives

Although some studies indicate the SCD may help people with IBD, the evidence is preliminary. Further research is needed.

One 2015 study of people with IBD showed that the subjects following the SCD had improved symptoms and quality of life. However, all participants’ disease was in remission, which indicates the SCD may only help people maintain a state of remission.

A 2017 analysis reviewed studies exploring the effect of diet on IBD. Some studies indicated symptom improvement among participants, and another showed that people on the SCD had more diverse bacteria in their gut than those following a Western diet.

A 2016 study showed that the SCD improved symptoms in people with IBD.

However, not all research on the SCD is encouraging.

Although there are potential benefits, there are several risks associated with the SCD.

Adherence challenges

The SCD’s limited permitted foods make it difficult to follow.

Because Gottschall recommends strict adherence, it poses a challenge for people who may not want to follow a restrictive diet.

However, there is some evidence that a more relaxed form of the diet can be beneficial to people long term. This means the strict SCD may be a good starting point for people with IBD, and they can adapt the diet to fit their lifestyle and symptoms going forward.

Vitamin and calorie deficiencies

Some scientists speculate the SCD may result in certain nutritional deficiencies due to its restrictive nature. These include:

The Crohn’s & Colitis Foundation also notes that the diet has the potential to affect growth in children.

Not universally beneficial

Doctors may not recommend the SCD for everyone with IBD.

Since the eating plan is high in fiber, it may not be a good choice for an individual with a significant number of small bowel structures. This is because the high fiber content could lead to an obstruction.

Impractical for some

The SCD’s strict criteria make it time-consuming and socially restrictive.

Since a major characteristic of the diet is cooking from scratch, people with families, busy schedules, and demanding jobs may find it too time-consuming. Additionally, people who live in food deserts may not have access to foods on the “allowed” list.

Due to the possibility of nutritional deficiencies, experts advise people following the SCD to contact a dietitian.

A dietitian can ensure a person is eating a nutritionally balanced diet, and they can also help them manage the issues associated with a restrictive eating plan.

The SCD is popular among people with IBD. It involves eating unprocessed foods and simple carbohydrates. It restricts complex carbohydrates and processed foods.

Some evidence indicates this diet may reduce IBD symptoms and bowel inflammation. However, its restrictive nature has multiple risks and may not be practical for everyone.

If a person is interested in trying the SCD, they should consult a dietitian or doctor.