The Specific Carbohydrate Diet (SCD)

It all starts with SIBO, otherwise known as Small Intestinal Bacterial Overgrowth. This occurs when there’s an abnormal increase in the number of bacteria in the small intestine, which can lead to symptoms like bloating, gas, diarrhea, and abdominal pain.

All “SIBO diets” have the same goal: to restore or maintain gut bacterial balance, so someone with SIBO feels better. The word “diet” is often associated with weight loss, but SIBO diets are not weight-loss plans; they are a part of SIBO management. They are meant to decrease symptoms in people who don’t feel well.

The Theory Behind the SCD

The guidelines of the SCD are based on the chemical structure of foods and how easily they are digested. The theory behind the SCD is that there are specific carbohydrates that promote inflammation and increase the number of “bad” gut bacteria. This increase in bad bacteria prevents proper absorption of nutrients and vitamins.

This resembles the process seen in SIBO, hence the thought behind using it to help manage SIBO. The allowed carbohydrates in this diet are simple monosaccharides (single molecules), which are easily digested and absorbed in the intestines. Complex disaccharides (double molecules) and polysaccharides (chain molecules) are not allowed.

Complex carbohydrates that are not easily digested can feed harmful bacteria, leading to bacterial overgrowth, irritation, and inflammation in the intestines. The diet works by starving these bacteria and restoring balance to the gut flora. As the microbiota begins to stabilize, the corresponding reduction of toxins and irritants in the intestines leads to decreased levels of inflammation.

A Food Guide for the SCD

Here is a chart of some foods to include and exclude on the Specific Carbohydrate Diet.

Category	Include	Exclude
Fruits	Fresh, frozen, raw, or dried fruits with no added sugar (apples, avocados, ripe bananas, berries of all kinds, coconut, dates, grapefruit, grapes, kiwi, kumquats, lemons, limes, mangoes, melons, nectarines, oranges, papayas, peaches, pears, pineapples, prunes, raisins, rhubarb, tangerines)	Canned fruits and most fruit juices, due to the common addition of sweeteners, preservatives, and processing aids
Dairy and Eggs	Cheeses such as cheddar, Colby, and Swiss; natural 30-day aged cow and goat cheeses (not Kraft); butter, ghee, and dry curd cottage cheese (DCCC); homemade yogurt fermented for at least 24 hours	Commercial yogurts, milk of any kind, cream, sour cream, ice cream; unnatural cheeses (Kraft and most mainstream shredded cheeses); cottage, cream, feta, gjetost, mozzarella, neufchâtel, primost, ricotta, and processed cheese spreads
Grains	None	All grains, including corn, wheat, wheat germ, barley, rye, oats, rice, buckwheat, millet, triticale, bulgur, spelt, and quinoa (this includes bread, pasta, and baked goods made with grain-based flour)
Meat	Fresh, unprocessed meats, poultry, and fish/shellfish without additives (chicken, turkey, beef, fish, pork, wild game, bacon, lamb)	Canned or processed meats: ham, processed sausages, lunch meats, bratwurst, turkey dogs, hot dogs
Beans and Legumes	Dried beans, lentils, split peas, peas, white beans, navy beans, lima beans, kidney beans, black beans, raw cashews, raw peanuts, and all-natural peanut butter	Soybeans, chickpeas (garbanzo beans), bean sprouts, mung beans, fava beans
Vegetables	Fresh or frozen forms of most commonly eaten vegetables (asparagus, beets, broccoli, brussels sprouts, cabbage, cauliflower, carrots, celery, cucumbers, eggplant, garlic, kale, lettuce, mushrooms, onions, peas, peppers, pumpkin, spinach, squash, string beans, tomatoes, watercress)	Canned vegetables, due to the usual addition of sugars, processing aids, and preservative chemicals
Starches	None	Starchy tubers such as potatoes, yams, sweet potatoes, and turnips; arrowroot, parsnip, cornstarch, tapioca starch
Nuts and Seeds	Almonds, pecans, Brazil nuts, hazelnuts, walnuts, cashews, chestnuts (no additives for butters, salted mixes, and flours)	None
Fats and Oils	Most oils	Canola oil and store-bought mayonnaise
Beverages	Weak tea or coffee, water, mineral water, club soda, dry wine, gin, rye, Scotch, bourbon, vodka	Instant coffee, most commercial juices, milk, soda pop, sweet wines, flavored liqueurs, brandy, sherry
Sweeteners	Honey	Sugar of any kind (cane, coconut, table, etc.), agave, molasses, syrup, maple syrup, sucrose, processed fructose including high-fructose corn syrup, and artificial sweeteners
Spices and Miscellaneous	Most non-mixed spices are allowed; screen for anti-caking agents and make sure the ingredients are listed	Mustard, cider and white vinegar, seaweed and seaweed byproducts

Whether the SCD is the right approach for you depends on your history and your symptoms, which is a conversation worth having with a clinician who can see both. As above, it is a way of managing symptoms rather than a weight-loss plan.