What is the SCD Diet Plan for Gut Health?

December 28, 2025 •

4 min read

Originally developed in the 1920s to treat celiac disease, the Specific Carbohydrate Diet (SCD) is a highly restrictive nutritional plan designed to heal the gut and reduce inflammation. By eliminating most carbohydrates and sugars, the SCD diet plan aims to starve harmful intestinal bacteria that contribute to digestive disorders like Crohn's disease and ulcerative colitis. This approach has gained significant attention for its potential benefits, though it requires strict adherence and careful monitoring.

Quick Summary

A detailed explanation of the Specific Carbohydrate Diet (SCD), an elimination diet that restricts complex carbohydrates to reduce gut inflammation. It covers allowed and restricted foods, its theory of action, and potential benefits and risks for individuals with inflammatory bowel diseases and other digestive issues.

Key Points

Restricts Complex Carbs: The SCD is an elimination diet that focuses on consuming only simple carbohydrates (monosaccharides) that are easily digested.
Targets Gut Health: Its primary goal is to rebalance the gut microbiome by removing complex carbs that feed harmful bacteria and yeast.
Popularized for IBD: The diet gained popularity for its use in managing inflammatory bowel diseases (IBD), such as Crohn's disease and ulcerative colitis.
Emphasizes Whole Foods: SCD-legal foods include fresh fruits, vegetables, unprocessed meats, and aged cheeses, but no grains or starches.
Requires Professional Guidance: Due to its highly restrictive nature and risk of nutrient deficiencies, the diet should be followed with medical supervision.
Involves a Strict 'Legal' List: Adherence relies on carefully following a list of allowed foods and avoiding all others, including most dairy and processed sugars.

The Vicious Cycle: How the SCD Diet Works

The Specific Carbohydrate Diet (SCD) is not a conventional diet but a nutritional therapy targeting specific digestive issues. The core theory, popularized by biochemist Elaine Gottschall, centers on a “vicious cycle” of gut inflammation. According to this theory, individuals with compromised digestive function cannot properly break down complex carbohydrates (like disaccharides and polysaccharides). These undigested carbs then remain in the gut, providing a food source for harmful bacteria and yeast.

This bacterial overgrowth leads to the production of acidic byproducts and toxins, which in turn irritate and damage the intestinal lining. The damage impairs the gut's ability to produce digestive enzymes, further hindering carbohydrate digestion and perpetuating the cycle of inflammation and microbial imbalance. The SCD aims to break this cycle by removing the fermentable carbohydrates that fuel this harmful bacterial overgrowth, allowing the gut to heal.

SCD Legal vs. Illegal Foods

The success of the SCD hinges on a strict list of allowed (“legal”) and prohibited (“illegal”) foods. Foods are categorized based on their carbohydrate structure, favoring simple carbohydrates (monosaccharides) that are easily absorbed.

Legal Foods (Allowed):

Meat and Poultry: Fresh, unprocessed meats, fish, and shellfish, along with eggs.
Fruits: Most fresh, frozen, or cooked fruits without added sugar.
Vegetables: Most vegetables, including leafy greens, carrots, and squash, but excluding starchy varieties.
Dairy: Aged cheeses (cheddar, Colby, Swiss) and homemade yogurt fermented for 24+ hours to eliminate lactose.
Legumes: Dried navy beans, lentils, and split peas that have been soaked.
Nuts and Flours: Most nuts (like almonds, walnuts) and nut flours.
Sweeteners: Honey.

Illegal Foods (Avoid):

Grains: All grains, including wheat, corn, rice, quinoa, and oats.
Starches: Starchy tubers like potatoes, sweet potatoes, and turnips.
Sugars: All processed sugars (sucrose, corn syrup), molasses, maple syrup, and most sugar substitutes.
Dairy: Commercial milk, yogurt, and most lactose-containing dairy products.
Processed Foods: Canned vegetables with additives, processed meats, and commercial condiments.
Certain Legumes: Soybeans and chickpeas.

Stages of the SCD

For those with severe digestive symptoms, the SCD often begins with an introductory diet for 2 to 5 days, focusing on easily digested foods like broths, gelatin, and homemade yogurt. This phase is designed to rest the gut and ease the transition. Following this, new “legal” foods are introduced gradually in stages, allowing individuals to monitor their body’s response and determine which foods are best tolerated. This phased approach is a key part of the diet's strategy for gut healing.

Potential Benefits and Drawbacks

Studies suggest the SCD can improve symptoms of inflammatory bowel diseases (IBD) like Crohn's disease and ulcerative colitis, and in some cases, lead to remission. This improvement is linked to reducing gut inflammation and restoring a balanced microbiome. However, the diet has significant drawbacks. It is extremely restrictive, making adherence challenging, and may lead to nutritional deficiencies if not carefully planned with a healthcare professional. The diet's long-term effectiveness compared to less restrictive diets is still under investigation.

Comparison with Other Diets


Feature	SCD Diet	Low-FODMAP Diet	Mediterranean Diet
Carb Restriction	Eliminates nearly all grains, starches, and processed sugars, allowing only monosaccharides.	Restricts short-chain fermentable carbohydrates (FODMAPs).	High in complex carbs from whole grains, fruits, and vegetables; low in red meat.
Dairy	Restricts most dairy; permits aged cheese and 24-hour homemade yogurt.	Restricts lactose-containing dairy.	Includes a moderate amount of dairy products.
Grains	All grains (including gluten-free) are prohibited.	Restricts high-FODMAP grains like wheat and rye; allows low-FODMAP grains like rice.	Includes whole grains as a staple food.
Legumes	Allows specific, properly soaked legumes like lentils and dried beans.	Restricts many legumes high in FODMAPs.	Encourages regular consumption of legumes.
Goal	Heals the gut lining and rebalances the microbiome by starving harmful bacteria.	Identifies specific carbohydrate triggers for symptoms; often temporary.	Promotes overall heart health and reduced inflammation through a balanced eating pattern.
Restrictiveness	Very high.	High during the elimination phase, followed by reintroduction.	Moderate and sustainable for long-term health.

Conclusion

The Specific Carbohydrate Diet is a highly restrictive elimination diet developed to treat gastrointestinal disorders by restoring the balance of the gut microbiome. It operates on the principle of eliminating complex carbohydrates that are believed to ferment in the gut, thereby starving harmful bacteria and reducing intestinal inflammation. While anecdotal and some small-scale studies suggest potential benefits for individuals with IBD, the diet's strict nature presents significant challenges, including high costs, time-consuming food preparation, and potential nutrient deficiencies. Anyone considering the SCD diet plan should do so under the supervision of a healthcare provider or a registered dietitian to ensure proper nutrition and minimize risks. More robust scientific research is needed to definitively confirm the diet's long-term safety and efficacy.

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Frequently Asked Questions

The main goal of the Specific Carbohydrate Diet (SCD) is to heal the gut and reduce inflammation by eliminating most carbohydrates, which are believed to feed harmful bacteria and worsen digestive disorders.

The SCD is often used to help manage symptoms for individuals with inflammatory bowel diseases (IBD) like Crohn's disease and ulcerative colitis, as well as celiac disease and chronic diarrhea.

Only specific carbohydrates that are classified as monosaccharides, which are single-unit sugars like glucose and fructose, are permitted because they are easy to digest.

No, all grains, including rice, wheat, corn, and oats, are prohibited on the SCD because they contain complex carbohydrates that are difficult to digest and ferment in the gut.

Challenges include the diet's highly restrictive nature, the time-consuming process of meal preparation, potential nutrient deficiencies, and difficulty socializing or dining out.

For some, the SCD may be followed for life to manage symptoms, while others may gradually reintroduce foods after a period of remission. Elaine Gottschall suggested staying on the diet for at least one year after symptoms disappear.

Some small studies and anecdotal evidence suggest the SCD can improve symptoms in people with IBD. However, more extensive and rigorous scientific research is needed to confirm its safety and long-term effectiveness.