Specific Carbohydrate Diet (SCD): A Detailed Beginner’s Guide
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The specific carbohydrate diet (SCD) eliminates all grains, sugars, and most milk products and processed foods.
It was created to treat celiac disease in the early 1920s, but it is now used to treat inflammatory bowel diseases like ulcerative colitis and Crohn’s disease.
This article explains what to eat and avoid on the SCD, its benefits and risks, and provides an SCD sample menu.
What is the specific carbohydrate diet (SCD)?
The SCD is a type of elimination diet that restricts specific types of carbs, namely those found in grains, milk, and processed foods.
It was created by pediatrician Dr. Sidney Haas in the 1920s to initially treat celiac disease, an autoimmune condition triggered by gluten (1).
Later, Elaine Gottschall, the mother of one of Haas’s patients published Breaking the Vicious Cycle: Intestinal Health Through Diet after her daughter’s inflammatory bowel disease (IBD) improved with the use of the SCD after just four weeks.
Gottschall theorized that the complex carbohydrates from grains and dairy products go undigested in people with IBD and ferment in the colon to produce acid and inflammatory byproducts, which worsen diarrhea and lead to bacterial overgrowth (1).
Conversely, she explains that simple carbohydrates, like those found in fruits and vegetables, are easily absorbed, leaving no byproducts that can be used to fuel inflammation or bacterial growth.
The release of her book popularized the SCD for treating Crohn’s disease and ulcerative colitis — two forms of IBD — and evoked passionate testimonials from its followers.
What the SCD allows
The SCD eliminates all grains, dairy products except for hard cheeses and yogurt fermented for 24 hours, sugars, and most food additives and preservatives.
The SCD prohibits the following foods (2):
- Sugars, including molasses, maple syrup, sucrose (table sugar), high-fructose corn syrup (HFCS), maltose, and isomaltose
- All grains, including corn, wheat, wheat germ, barley, oats, rice, and grain-based products, including bread, pasta, and baked goods made with grain-based flour, and breakfast cereals
- Some legumes and beans, including garbanzo beans, pinto beans, canned beans, and soy
- Starchy tubers, such as potatoes, sweet potatoes, and turnips
- Canned and processed meats, including salami, pepperoni, lunch meats, and canned tuna and chicken
- Dairy products rich in lactose, including milk, mild cheddar cheese, store-bought yogurt, cream, sour cream, and ice cream
- Candy and chocolate
- Soy and soy products
The SCD allows the following foods (2):
- Fresh meats without additives, beef, pork, and goat
- Poultry and eggs, chicken, turkey, duck, quail, etc.
- Fish and shellfish, including lobster, crab, clams, shrimp, tuna, scallops, salmon, cod, herring, sardines, etc.
- Certain legumes, including dried navy beans, peas, split peas, lima beans, and all-natural peanut butter
- Certain cheeses, including cheddar, Colby, and Swiss
- Homemade yogurt fermented for at least 24 hours
- Fresh or frozen vegetables and fruits, like apples, bananas, berries, broccoli spinach, mushrooms, peppers, etc.
- Most nuts and nut flours, like almonds, chestnuts, hazelnuts, pecans, and walnuts
- Most cooking oils, including extra-virgin olive oil
- Unsweetened tea and coffee
- Honey as a sweetener
How to follow the diet
The SCD is a type of elimination diet, similar to the GAPS diet — which stands for Gut and Psychology Syndrome.
An elimination diet generally consists of three phases — elimination, maintenance, and reintroduction.
During the elimination phase, eliminate foods that the SCD prohibits, including grains, most dairy products, and processed foods, and consume only foods that the diet allows.
The next phase is the maintenance phase, during which, you continue to eat only the foods allowed.
Gottschall recommends following the maintenance phase for at least one year after symptoms have disappeared.
The final phase is the reintroduction phase, which involves reintroducing the foods you eliminated, one at a time, slowly over several weeks while you look for symptoms.
Although Gottschall doesn’t recommend a reintroduction phase, you may be able to tolerate some of the foods you initially eliminated without experiencing symptoms, allowing for a more liberalized diet.
For example, in one study, children with Crohn’s disease who followed a modified SCD with oats and rice still experienced symptom relief and reductions in inflammatory markers (3).
What’s more, a different study showed that the SCD was no more effective than the Mediterranean diet for alleviating symptoms or decreasing markers of inflammation in adults with Crohn’s disease after 12 weeks (4).
The Mediterranean diet emphasizes fruits, vegetables, whole grains, and healthy proteins while limiting foods high in added sugar, sodium, and unhealthy fats.
These results suggest that the SCD may be a good place to start but it may not need to be as strict to still offer symptom relief.
And although Gottschall recommends following the SCD diet for at least one year after your symptoms disappear, you can try to reintroduce foods after only a few months (5).
Three-day sample SCD menu
Here is a 3-day sample SCD menu:
- Breakfast: scrambled eggs with spinach and berries
- Lunch: split pea salad
- Snack: homemade yogurt and almonds
- Dinner: chicken and veggie stir fry with zucchini, squash, carrots, and asparagus
- Breakfast: banana pancakes made with coconut flour
- Lunch: bunless burgers with buttered snap peas and carrots
- Snack: homemade yogurt and a ripe banana
- Dinner: sliced roast beef, zucchini fries, and a caesar salad
- Breakfast: scrambled eggs with buttered biscuits made with almond flour
- Lunch: turkey meatballs with zucchini noodles and home-made marinara sauce
- Snack: homemade yogurt and walnuts
- Dinner: taco salad with roasted brussels sprouts
Here is the recipe for SCD yogurt to yield one quart or four cups:
- 32 oz organic whole milk
- starter culture such as Yogourmet (5-gram packet)
- Heat milk until it reaches 180 degrees Fahrenheit.
- Cool to 110 degrees Fahrenheit and mix in the starter culture.
- Keep at 110 degrees Fahrenheit and let sit for 24 hours (it’s easiest if you make this using a yogurt maker).
The SCD has been shown to relieve intestinal inflammation and reduce or eliminate symptoms in children and adults with IBD.
In one study, 10 adolescents with mild-to-moderate Crohn’s disease were randomized to one of three diets — the SCD, a modified SCD with oats and rice, or a whole food diet that eliminated wheat, corn, sugar, milk, and food additives (3).
After 12 weeks of following the diets, all participants achieved clinical remission and experienced reductions in markers of inflammation to varying degrees, but those who followed the SCD and modified SCD experienced the greatest improvements.
In a longer study, adults with IBD who followed the SCD for up to five years showed significant improvements in symptoms and intestinal inflammation and were able to discontinue medications used to control their IBD (6).
What’s more, a review of 50 case reports found that adults with IBD who followed the SCD experienced remission, improved their quality of life, and could discontinue medications used to treat their IBD like anti-inflammatory drugs (7).
Still, the effectiveness of the SCD for relieving symptoms and reducing inflammation varies, and not everyone with IBD experiences symptom relief with the SCD.
If you don’t experience symptom relief after one month of following the diet you should discontinue it (6, 8).
Risks and downsides
The primary risk with the SCD is the potential for nutritional deficiencies.
Any time you eliminate certain foods — or entire food groups as with the SCD — you increase the risk of developing nutrient deficiencies.
But, despite eliminating grains and most dairy products, a study in children and teens with IBD found that the SCD is nutritionally comparable to the diets of healthy children and teens (9).
However, the participants and their parents in this study were counseled and educated by a registered dietitian on the diet, which likely increased the nutritional quality of their diets.
Nutrients that the SCD may lack include:
- thiamin (vitamin B1)
- vitamin D
Taking a multivitamin supplement can help ensure that you’re getting enough of these nutrients and others that you may be lacking.
Beyond the potential for nutritional deficiencies, the SCD can be very difficult to follow, even in the short term, due to its restrictiveness (10).
It also requires a lot of meal planning and prepping, which can be very time-consuming.
But as previously mentioned, some diet liberalization is possible.
The bottom line
The SCD emphasizes whole, nutrient-dense foods and excludes simple sugars, grains, most dairy products, and food additives and preservatives.
The diet has been shown to relieve symptoms and decrease intestinal inflammation in both children and adults with IBD, such as Crohn’s disease and ulcerative colitis.
The diet’s restrictiveness increases the risk of nutritional deficiencies, especially if you aren’t working with a registered dietitian, but taking a multivitamin can help cover any nutrient shortfalls.