A low-FODMAP diet is proven to relieve symptoms of gastrointestinal disorders like irritable bowel syndrome (IBS) and small intestinal bacterial overgrowth (SIBO). However, the diet requires a disciplined approach to get started on the right foot.
In this guide, I answer some of the most common questions about starting a low-FODMAP diet. I also share the resources that have helped me through my own low-FODMAP journey. This guide will strengthen your understanding of FODMAPs and explain the three steps of a low-FODMAP diet. As with anything related to your health, you should consult a healthcare professional or dietician before making significant changes to your diet or lifestyle.
If this is your first time reading about FODMAPs or you are still confused about the low-FODMAP diet and its relation to a paleo or gluten-free diet, I recommend reading these FODMAP FAQs first.
What are FODMAPs?
Understanding what FODMAPs are and how your body reacts to them is the focus of a low-FODMAP diet. This blog post will get a bit technical, but it’s essential to understand.
FODMAP stands for “Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols,” which involves carbohydrates that cannot be digested by the body. When these carbs reach your colon, your gut bacteria use them for energy but release hydrogen in the process. This can trigger symptoms like stomach pain, bloating, gas, diarrhea, and other uncomfortable changes for people with IBS or SIBO.
The common groups of FODMAPs include:
- Fructose, or sugar, which is present in many fruits and vegetables, as well as table sugar and most sweeteners
- Lactose, a carb found in dairy products
- Fructans, which are unable to be absorbed because our bodies lack enzymes to break them down. Wheat is the primary source of fructans for most people
- Galactans, which our bodies also cannot break down and are commonly found in beans and lentils
- Polyols, or sugar alcohols like xylitol, sorbitol, maltitol, and mannitol, found in some fruits, vegetables, and even mints or gum
How to Start a Low-FODMAP Diet in 3 Steps
The goal of a low-FODMAP diet is to eliminate your consumption of high-FODMAP foods and replace them with low-FODMAP or FODMAP-free alternates.
Each person will react differently to the various FODMAPs, and the reaction depends on the portion size of the FODMAP consumed. Given this complexity, a low-FODMAP diet consists of three steps to understand what foods are most triggering and in what quantities:
Step 1: Elimination Phase
The first phase of a low-FODMAP diet removes high-FODMAP foods from your diet to return your body to a baseline of sorts. For two to six weeks, swap high-FODMAP foods for FODMAP-free and low-FODMAP alternatives. This guide will show you what to look out for, and you will ideally start to feel the benefits of removing FODMAPs from your diet quickly—goodbye cramps, bloating, and diarrhea!
Although you will feel some relief from your typical trigger symptoms, it is essential to note that the elimination phase cannot span more than six weeks. Such a restrictive diet can leave your body deprived of essential nutrients and prebiotics, and you need to start step two once your body has reached a less triggered state.
Step 2: Re-challenge or Reintroduction Phase
After doing the elimination phase, you can start the re-challenge or reintroduction phase. Add FODMAPs back into your diet, one FODMAP at a time, one food at a time. Monitor your tolerance after increasing your serving of the food each day for three days. For example, you could test your fructose limits by increasing your Red Delicious apple intake over three days and then switching to a Fuji apple after you have tested the effects of a Red Delicious apple on your body.
You’ll want to make a note of—and discontinue eating—any food and the related FODMAPs that trigger your IBS symptoms. Serving size is a critical factor in this step, as you can trigger IBS symptoms by eating too much of a low-FODMAP food.
Step 3: Keep testing
After the initial elimination and re-challenge phase, continue testing new foods every few months to see if your tolerance has changed. You could become more receptive to foods/FODMAPs that you previously could not eat, so it is worth testing a small amount of a previously triggering FODMAP. For us, that means we’ve been able to re-introduce avocados, asparagus, and artichokes in limited amounts (yay!), but we still stay away from onions and garlic completely. Unfortunately, there isn’t a one-size-fits-all low FODMAP diet food list.
Where can I find some resources to help me with the low-FODMAP diet?
A few other resources I recommend for your low-FODMAP diet journey:
- Monash University’s low FODMAP diet site has countless resources to understand the low-FODMAP diet better. Monash also has a low FODMAP diet app with a whole library of low-FODMAP recipes and information on foods’ FODMAP content.
- Fody Foods sells delicious low-FODMAP shelf-stable foods like sauces, seasonings, and snack bars, and the site also shares recipes you can try.
- Schär Gluten-Free is known for its bread and crackers, and also has many low-FODMAP items for sale.
- Thrive Market has an entire low-FODMAP section to its online grocery store.
Do you have any other questions or want to share your tips for starting a low-FODMAP diet? Let me know in the comments!