Is ratatouille low in fodmap? Navigating Ingredients for a Gut-Friendly Meal

November 14, 2025 •

4 min read

According to research by Monash University, the traditional ratatouille recipe contains several high-FODMAP ingredients, such as onions and garlic. However, with simple substitutions and careful portioning, a delicious and low fodmap ratatouille can be easily achieved.

Quick Summary

Traditional ratatouille often contains high-FODMAP onions and garlic, making it unsuitable for a restrictive diet phase. The classic dish can be made gut-friendly by using safe ingredient swaps and adhering to recommended portion sizes for vegetables and tomatoes.

Key Points

Onions and Garlic: Traditional ratatouille ingredients like onions and garlic are high in fructans and should be replaced with substitutes like garlic-infused oil and scallion greens.
Portion Control: Vegetables like eggplant and zucchini are only low FODMAP in specific portion sizes, so careful measurement is necessary to prevent triggering symptoms.
Tomato Products: The FODMAP content of tomatoes varies. Canned and concentrated products can be high in fructose in large servings, so stick to Monash-approved portion sizes.
Infused Oils: Using oils infused with garlic or onion is a safe way to add flavor, as the FODMAPs are not fat-soluble and do not leach into the oil during cooking.
Herb Flavoring: Fresh, low-FODMAP herbs such as basil, thyme, and rosemary are essential for building complex flavors in a modified ratatouille.
Preventing Stacking: Be mindful of combining multiple low FODMAP ingredients, as portions can accumulate and push the total FODMAP load of a meal into a high range.

Decoding Ratatouille for a Low FODMAP Diet

Ratatouille is a classic French Provençal vegetable stew featuring eggplant, zucchini, bell peppers, tomatoes, onions, and garlic. While it is celebrated for its fresh, wholesome ingredients, its traditional preparation can pose a challenge for those following a low FODMAP diet. The good news is that with a few smart modifications, you can enjoy all the rich flavor of this dish without the digestive distress. A low FODMAP diet is designed to help manage symptoms of Irritable Bowel Syndrome (IBS) by temporarily restricting fermentable carbohydrates that can trigger discomfort.

The Problem with Traditional Ratatouille Ingredients

The primary culprits in a traditional ratatouille are onions and garlic. Both of these are concentrated sources of fructans, a type of fermentable carbohydrate that is often poorly absorbed by the small intestine. While beneficial for gut health in many people, fructans can cause bloating, gas, and pain in individuals with IBS. Since fructans are water-soluble, cooking onions and garlic in a sauce or stew will infuse the entire dish with these FODMAPs, making simply removing the pieces ineffective. Other ingredients can also be problematic depending on portion size:

Tomatoes: Some tomato products, particularly canned varieties, are high in fructose, which can be a trigger in larger amounts.
Eggplant: This vegetable contains sorbitol and is low FODMAP only in specific serving sizes. Monash University recommends no more than 1 cup (75 g) per serving.
Zucchini: Similarly, zucchini contains fructans and is only low FODMAP in a restricted portion of ⅓ cup (65 g).

Making a Delicious Low FODMAP Ratatouille

Creating a gut-friendly version of ratatouille is a straightforward process of replacing high-FODMAP ingredients with tested, safe alternatives. The key is to focus on maximizing flavor through other methods.

Here are some essential swaps and guidelines:

Garlic: Replace fresh garlic with garlic-infused olive oil. Fructans are not fat-soluble, so the flavor transfers to the oil without the FODMAPs. You can use a commercially certified product or make your own carefully.
Onions: Use the green tops of scallions or leeks. The white bulbs and green bottoms are high in fructans, but the dark green parts are low FODMAP and provide a milder onion-like flavor.
Tomatoes: Be mindful of portion sizes. Common tomatoes are low FODMAP in servings of ½ medium tomato (65 g), and cherry tomatoes are low FODMAP at 3 medium tomatoes (45 g). Use low-FODMAP canned tomatoes, but stick to the recommended portion of ½ cup (100g) per serving to avoid excess fructose.
Vegetable Portions: To prevent FODMAP stacking, adhere to the recommended low FODMAP serving sizes for eggplant (75 g) and zucchini (65 g). Combining multiple low FODMAP ingredients can increase the overall FODMAP content of a dish.
Herbs: Use fresh, low-FODMAP herbs like basil, thyme, and rosemary generously to build complex flavors.

Comparison Table: High FODMAP vs. Low FODMAP Ratatouille


Ingredient Category	Traditional (High FODMAP)	Low FODMAP Alternative
Aromatics	Onion, garlic, shallots	Garlic-infused olive oil, green scallion tops, green leek tops
Tomatoes	Large servings of canned tomatoes; sauces with onion/garlic	Canned or fresh tomatoes in Monash-approved portion sizes
Eggplant	Unlimited servings (high sorbitol in large amounts)	Portion-controlled serving (up to 75 g)
Zucchini	Unlimited servings (high fructans in large amounts)	Portion-controlled serving (up to 65 g)
Herbs	Basil, thyme, rosemary	Generous quantities of basil, thyme, rosemary
Cooking Oil	Regular olive oil	Certified garlic-infused olive oil or regular olive oil

Preparing a Gut-Friendly Ratatouille

Start by heating garlic-infused olive oil in a large pot. Add diced eggplant, zucchini, and red bell peppers (which are low FODMAP in moderation) and sauté until they begin to soften. Add your carefully measured low-FODMAP canned tomatoes, along with fresh thyme and rosemary sprigs. Simmer the mixture for 20-30 minutes, allowing the flavors to meld. Stir in the green tops of scallions and fresh basil toward the end of cooking for a vibrant finish. This method ensures that the final dish is rich in flavor while staying well within the low FODMAP guidelines.

Conclusion

While traditional ratatouille is not low in FODMAPs, modifying the recipe is simple and yields a delicious, gut-friendly result. By making key ingredient swaps, primarily replacing onions and garlic with suitable alternatives like garlic-infused oil and green scallion tops, and by carefully controlling portions of other vegetables, individuals with IBS can confidently enjoy this classic dish. This approach proves that managing digestive symptoms doesn't mean sacrificing flavor or variety. With knowledge of low FODMAP portions and substitutes, you can continue to enjoy a wide array of satisfying meals. For more detailed information on serving sizes and ingredients, refer to the official Monash University FODMAP Diet App.

Frequently Asked Questions

Traditional ratatouille is high in FODMAPs mainly due to the use of onions and garlic, both of which contain fructans. Larger portions of canned tomatoes and other vegetables like eggplant and zucchini can also contain problematic FODMAP levels.

A great alternative for garlic is to use garlic-infused olive oil, as the fructans do not dissolve in oil. For onions, you can use the green parts of scallions or leeks, which are low FODMAP while the white parts are not.

Yes, canned tomatoes can be low FODMAP, but only in specific, smaller portion sizes, such as ½ cup (100 g). Exceeding this amount can introduce moderate to high levels of fructose.

Excellent low FODMAP vegetables include eggplant, zucchini, and red bell peppers, as long as you stick to their tested low FODMAP portion sizes. You can also use other safe ingredients like common tomatoes within guidelines.

Yes, you can use regular olive oil. The purpose of using infused oil is simply to add flavor. If you don't need the garlic taste, a standard olive oil works fine and is low FODMAP.

Absolutely. By utilizing garlic-infused oil for a savory base, green parts of scallions for a mild onion flavor, and generous amounts of low-FODMAP herbs like basil and thyme, your ratatouille can still be incredibly rich and delicious.

To prevent FODMAP stacking, use the Monash app to carefully adhere to the recommended low FODMAP serving sizes for each ingredient, especially those like zucchini and canned tomatoes. Ensure your overall meal stays within acceptable limits by not over-portioning any single ingredient.