Low FODMAP diet vs Specific Carbohydrate Diet

From Alana: I’m very excited to announce that we have our first guest blogger! Katelyn is in training to become a registered dietitian and she is currently the driving force behind the Nicer Foods blog. She has written a great article about the differences between the specific carbohydrate diet and the low FODMAP diet.

Update: Since writing this article Katelyn has become a registered dietitian (see bio below) and Nicer Foods was sold to FODY Food Company in 2016.

What is the Specific Carbohydrate Diet?

The Specific Carbohydrate Diet (SCD) was created for those with ulcerative colitis, inflammatory bowel disease, irritable bowel syndrome, and other digestive issues (1). The diet eliminates complex carbohydrates, lactose, sucrose, and most processed foods (1). This means that those on the SCD cannot eat grains, processed meats, canned fruits and vegetables, certain legumes, starches, or tubers (and you thought low FODMAP was hard!). The idea behind the diet is that only single sugar molecules (monosaccharides) can be absorbed by the small intestine and the rest will be broken down (fermented) by bacteria and yeasts that live in the intestines (2). The by-products of this fermentation process are thought to be toxic to the intestines and contribute to inflammation, although these claims have yet to be proven (2).

Low FODMAP diet vs Specific Carbohydrate Diet

The low FODMAP diet and the Specific Carbohydrate Diet were both created to reduce the amount of carbohydrates in the intestines. The SCD restricts all sugars except for monosaccharides (glucose, fructose, galactose), while the low FODMAP diet only restricts fermentable carbohydrates. As registered dietitian Patsy Catsos mentions in her comparison of the two diets, the SCD was created before fructose malabsorption was widely recognized as a gastrointestinal (GI) trigger (3). The SCD encourages the use of honey as a sweetener, which as you probably know, contains a lot of fructose and can cause GI symptoms. Additionally, the SCD allows certain fructan-containing foods such as onions and garlic. Fructans, AKA fructo-oligosaccharides, are part of the O group in the FODMAP acronym and are restricted during the elimination phase of the low FODMAP diet. With that mind, it would be difficult to recommend the SCD to someone with IBS, especially if they have known intolerances to any of the foods mentioned.

The Specific Carbohydrate Diet requires long-term adherence and even promises healing of the gut, while the low FODMAP diet is short-term and is designed to control IBS symptoms and identify trigger foods (1). At this point, there is no research to suggest that the SCD can deliver on its promises and heal those with IBS, but there are a variety of clinical studies that show that the low FODMAP diet can improve the symptoms of IBS (4 5 6).

If the challenge phase of the low FODMAP diet has taught us anything, it’s that everyone has different trigger foods. The low FODMAP diet can help you identify these triggers and spare you from a long-term restrictive diet, such as the Specific Carbohydrate Diet.