What is the primary goal of the specific carbohydrate diet?

October 30, 2025 •

3 min read

Initially developed in the 1920s to treat celiac disease, the specific carbohydrate diet (SCD) is a restrictive eating plan based on a key scientific theory. The primary goal of the diet is to address the root cause of digestive issues, particularly in cases of inflammatory bowel disease (IBD), by eliminating specific types of carbohydrates.

Quick Summary

The specific carbohydrate diet aims to break the cycle of inflammation, bacterial overgrowth, and malabsorption by eliminating complex carbohydrates that are difficult to digest. It focuses on easily absorbed monosaccharides to promote intestinal healing and reduce digestive symptoms.

Key Points

Heal the intestinal lining: The SCD's main goal is to promote healing of the gut by reducing inflammation and irritation.
Target bacterial overgrowth: By eliminating complex carbohydrates, the diet starves harmful bacteria and yeast that feed on poorly digested sugars.
Improve nutrient absorption: Restoring the intestinal lining and balancing gut flora allows for more efficient digestion and absorption of nutrients.
Break the 'vicious cycle': The diet is based on the theory of stopping a self-perpetuating cycle of malabsorption, bacterial fermentation, and inflammation.
Reduce inflammation: By controlling bacterial byproducts and promoting healing, the SCD aims to lower chronic inflammation in the gut.
Provide digestible carbohydrates: The diet focuses on monosaccharides, single-molecule carbohydrates that require minimal digestion, to reduce digestive stress.

The Core Theory: Breaking the Vicious Cycle

At the heart of the specific carbohydrate diet (SCD) is the theory, popularized by biochemist Elaine Gottschall, of the "vicious cycle" of intestinal damage. This cycle involves the malabsorption of complex carbohydrates, which then feed harmful bacteria and yeast in the small intestine. The fermentation byproducts from this bacterial overgrowth further irritate and damage the intestinal lining, impairing nutrient absorption and enzyme production.

How Carbohydrate Structure Impacts Digestion

The SCD aims to interrupt this cycle by allowing only carbohydrates that are easy to absorb. The diet classifies carbohydrates as "legal" or "illegal" based on their structure. Legal carbohydrates are monosaccharides (single molecules) like glucose and fructose, which are easily absorbed. Illegal carbohydrates include disaccharides, oligosaccharides, and polysaccharides (complex sugars) found in grains, starchy vegetables, and processed foods, which require more digestion. By removing complex carbohydrates, the diet seeks to lessen the food source for harmful bacteria, reducing fermentation and digestive problems. The primary aim is to promote intestinal healing by addressing the causes of irritation and inflammation. Depriving harmful gut bacteria of their food is a main mechanism. This can allow the gut environment to improve and the intestinal lining to repair, potentially enhancing digestive function and nutrient absorption. This healing and reduced inflammation are key for managing conditions like IBD.

Who is the Specific Carbohydrate Diet For?

The SCD is used for various gastrointestinal disorders. It is often applied to Inflammatory Bowel Disease (IBD), including Crohn's disease and ulcerative colitis. It may also be used for celiac disease, Small Intestinal Bacterial Overgrowth (SIBO), chronic diarrhea, and other gut issues.

The 'Legal' and 'Illegal' Foods of SCD

Adhering to specific food lists is essential. Allowed foods include unprocessed meats, most fruits and non-starchy vegetables, homemade 24-hour fermented yogurt, aged cheeses, eggs, nuts, nut flours, certain legumes, and honey. Forbidden foods encompass all grains, most grain products, starchy vegetables, processed sugars, high-lactose dairy, most artificial sweeteners, canned foods with additives, soy products, and most store-bought sauces.

Comparing SCD with other Therapeutic Diets


Feature	Specific Carbohydrate Diet (SCD)	Low-FODMAP Diet
Core Goal	Heal the gut by eliminating carbohydrates that feed harmful bacteria and yeast.	Manage symptoms like bloating and gas by reducing fermentable carbohydrates.
Mechanism	Targets carbohydrate structure; eliminates all di-, oligo-, and polysaccharides.	Targets fermentable short-chain carbohydrates (FODMAPs).
Restrictions	More restrictive in the long term; eliminates grains, most dairy, and starches indefinitely.	Allows for systematic reintroduction of foods.
Dairy	Restricts all high-lactose dairy; allows homemade 24-hour yogurt and aged cheeses.	Restricts high-lactose dairy; focuses on portion sizes and specific dairy products.
Carbs Allowed	Allows easily absorbed monosaccharides found in fruits, vegetables, and honey.	Allows some carbs, but restricts specific types found in fruits, vegetables, and grains.

Important Considerations and Risks

The SCD is highly restrictive and requires consultation with a healthcare professional. It can be difficult to maintain and may not suit everyone. Eliminating food groups like grains and dairy can pose a risk for nutrient deficiencies. Working with a registered dietitian is recommended to ensure adequate nutrition.

Conclusion: The Goal of Intestinal Healing

The primary goal of the specific carbohydrate diet is to restore digestive health by interrupting the cycle of bacterial overgrowth, malabsorption, and inflammation. By allowing only easily digestible carbohydrates, the diet aims to reduce harmful gut microbes and support intestinal healing. This diet is rigorous and requires professional medical guidance, especially for individuals with chronic inflammatory conditions like IBD.

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Frequently Asked Questions

The core theory is that intestinal inflammation and damage are caused by a "vicious cycle" involving the malabsorption of complex carbohydrates, which then feed harmful gut microbes and produce irritating byproducts.

The diet only allows monosaccharides, which are single-molecule carbohydrates like glucose, fructose, and galactose, as they are easily absorbed without extensive digestion.

Forbidden carbohydrates include complex sugars such as disaccharides (e.g., lactose and sucrose) and polysaccharides (starches in grains and starchy vegetables).

The SCD is most commonly used for inflammatory bowel diseases (IBD), such as Crohn's disease and ulcerative colitis, as well as celiac disease and other chronic digestive disorders.

Yes, due to its restrictive nature, the SCD has the potential to cause nutritional deficiencies. It is important to work with a healthcare professional or registered dietitian to ensure adequate intake of all essential nutrients.

While both diets restrict certain carbohydrates, the SCD is generally more restrictive and focuses on healing the gut lining by addressing the structure of carbs. The Low-FODMAP diet is more focused on managing symptoms by restricting specific fermentable carbohydrates and involves a reintroduction phase.

Some small studies have shown promising results for symptom improvement and reduced inflammation in IBD patients, particularly children. However, research is still limited, and more robust studies are needed to confirm its effectiveness.

Homemade yogurt is allowed only when fermented for at least 24 hours. This extended fermentation process ensures that the lactose (a disaccharide) is broken down into easily digestible monosaccharides, primarily galactose.