Low FODMAP Diet for SIBO & IBS (Expert Interview with Kate Scarlata)

Low FODMAP Diet for IBS Interview with Kate Scarlata, RDN

About Kate

Kate Scarlata is a mom, wife, sister, dietitian, runner, dog lover and foodie.  She is passionate about digestive health, nutrition, and using the low FODMAP diet to help patients heal with food. She began her career in nutrition at Simmons College in Boston and finished her postgraduate training at the Brigham and Women’s Hospital, a Harvard Medical School teaching affiliate.

She is also a New York Best Selling Book co-author, with her book 21 Day Tummy that helps people manage common digestive health issues and lose weight.

In this question & answer, we discuss the low FODMAP diet and how it can address and help manage IBS and SIBO symptoms. The Low FODMAP diet is one of the most effective SIBO diets with the most research in IBS.

Question & Answer

Q: What made you interested in becoming a dietitian and specifically focusing on helping people with digestive disorders?

Kate: I decided to become a dietitian way before it was a popular thing to do! I have been a dietitian for 30 years, which is somewhat hard to believe!  After about 8 years in the business, I had emergency surgery for a strangulated small intestine (scar tissue from an ovarian cyst removal wrapped around my intestine) that required 6 feet of my small intestine to be removed.  Having a major change in the way my body processed food, I started to take a deep dive into the science to better understand my body and to help others.

Starting a Low FODMAP Diet

low fodmap diet for sibo

Q: How do you determine how to customize the Low FODMAP diet for each individual? It can be overwhelming when someone is just given a food list from their doctor. What is your process? How do you progress from the elimination phase?

Kate: In a way, I look at each of my clients as a blank canvas. I try to capture a full medical history including how and when their digestive symptoms started, their current symptoms, what they hope to get out of a nutrition visit with me. (I believe strongly in patient shared decision making!)  Based on their symptoms and medical history, I adjust their diet based on how food typically impacts symptoms. I don’t believe everyone needs to start at a full elimination diet. And yes, I agree, receiving a food list with no instruction is a disservice to patients. After the patient has had some time calming the gut down, which often requires more than diet alone, we move on to the reintroduction phase.  I may introduce in one of two ways—the patient may be missing a particular food –and we try it OR, I do a more systematic approach, testing foods in each FODMAP sub-type (lactose, fructose, fructans etc.)

Q: Have you found certain foods are better for people with diarrhea vs constipation or do you usually see good results sticking to normal Low FODMAP diet principles for each person?

Kate: Truthfully, everyone is a bit different! But, as a general rule, I do find colonic gas to be a bigger problem for those with constipation–so the oligosaccharides (fructan/GOS), the “o” in FODMAPs are often a bigger trigger for these patients. Excess sorbitol is well documented to contribute to diarrhea–but again, everyone is a bit different.

Long-Term Strategy with Diet


Q: Sometimes patients feel better when they stay on a Low FODMAP diet continuously. What do you usually recommend for patients if they are going to be sticking to a FODMAP conscious diet for the long term? Is this healthy? And do you usually recommend gradually incorporating a wider range of foods over time?

Kate: When you finally feel better after sometimes years of digestive distress, it can be fearful to add foods back to the diet. But, being on a restrictive diet–can reduce the quality of life by limiting social engagements and enhancing food fear.  The low FODMAP diet can meet nutritional needs when done properly, but it does change the gut microbial environment–changing the acidity of stool and decreasing probiotic microbes. Acid in the stool is protective by minimizing the growth of pathogenic microbes in the colon.  I absolutely encourage my patients to expand their diet.

Fasting Time Between Meals

fasting between meals sibo

Q: Some SIBO experts recommend allowing fasting time between meals. Do you recommend this to SIBO patients when using the Low FODMAP diet? If so, how long do you usually recommend?

Kate: I do recommend fasting about 3-4 hours between meals (water or calorie-free beverages are okay to consume in between meals).  That being said, I encourage my patients to listen to their body. If they feel hungry and desire something to eat, that ‘trumps’ the meal spacing rule. Sometimes we just need to eat…and that is absolutely okay. Trying to space meals when you can allow the migrating motor complex (MMC) the opportunity to initiate a cleansing wave–washing out excess food and bacteria. The MMC only occurs in the fasting state–so not eating between meals allows it to happen more regularly. This may be helpful in managing SIBO.

Q: What do you recommend for people with blood sugar issues and SIBO. Is it more important to focus on healthy blood sugar levels than allowing fasting time between meals? What tips do you give to people with SIBO who are also experiencing blood sugar issues?

Kate: I think it is absolutely possible to do fasting of 3 hours for most people with blood sugar issues if they eat a balanced plate at their meal time (carbs with fiber, protein, produce and healthy fat). If a person is eating protein and vegetables only—their blood sugar may plummet.  Low blood sugar can be a sign that the patient has an overgrowth in hydrogen-producing and methane-producing bacteria–and this should be evaluated by a breath test and treated accordingly.

Dealing with Fructose Malabsorption in SIBO

fructose malabsorption

Q: There are many people with SIBO who have issues with fructose malabsorption even with Low FODMAP fruits. Do you still recommend eating fruits for these people and what is your strategy?

Kate: I start with lower carb, low FODMAP fruits to see if they can tolerate them, like one small kiwi or a few blueberries. Rather than forgo a whole food group–we make some adjustment to see what works. Fructose intolerance and food intolerance, in general, occurs in part due to SIBO. The bacteria are in the wrong place in large numbers and get to the food before the food is digested. Fructose is very accessible to bacteria–as a small, one chain sugar. Additionally, fructose is absorbed slowly by an inefficient mechanism–and its absorption occurs along the entire small intestine– so at some point, it will meet up with bacteria.

Tips During a Flare

Q: What are your diet tips for people who are in a flare up period and can’t tolerate much? Do you recommend things like soups, smoothies, and lowering the number of FODMAPs during these situations?

Kate: Yes, soups and smoothies made low FODMAP can be very soothing during a flare. Steeping a small piece of ginger root in hot water and sipping this is a great anti-nausea trick too.

Caffeine and Alcohol Consumption with IBS

caffeine and alcohol

Q: What advice do you give to people about caffeine and alcohol consumption with IBS? Do you find people can tolerate these substances in small amounts?

Kate: For IBS-C, caffeine can help, actually.  But both caffeine and alcohol are Gi irritants–so moderation is key.  Some sources of alcohol are FODMAPs too–such as rum.

Fermented foods in SIBO patients

Q: Do you find that fermented foods are good for people with SIBO? Sometimes patients can react negatively to probiotics and fermented foods with SIBO.

Kate: Some fermented foods seem to work well with SIBO patients and others less so.  This is likely due to the fact that fermenting foods can decrease the FODMAPs such as sourdough bread and yogurt with live cultures–or increase the FODMAP content such as sauerkraut and kombucha.  If your small intestine is slow moving–which is often the case in SIBO–adding more live microbes via some fermented foods may not be helpful.

Kate’s Favorite Quick Recipe

brown rice bowl low fodmap

Q: What is your favorite Low FODMAP recipe when you need something quick without a lot of cooking time?

Kate: I am all about a rice or quinoa bowl. I love Trader Joe’s frozen brown rice or quinoa that I can heat up in my microwave, I top it with grated carrots, chopped kale, pumpkin seeds or walnuts. Drizzle with lemon juice and olive oil and top with leftover chicken or an egg.

See more information on the Low FODMAP diet or other diets used to heal your gut. You can also check out Kate’s resources here.

Also don’t forget to check out our SIBO Survivor Cookbook to explore our vast collection of tasty, gut-friendly, and easy to prepare recipes. Get the E-book here!

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