Are Tomatoes Low FODMAP? Fresh, Canned, Paste, and Sauce Guide

Yes, fresh tomatoes are low FODMAP at standard serving sizes and are safe for most people with IBS. A common tomato (about 75g) contains only small amounts of fructose and no significant levels of other FODMAPs. Tomatoes are one of the most versatile low-FODMAP vegetables, but things get more complicated with concentrated forms like paste, sun-dried tomatoes, and commercially prepared sauces.

Understanding how different tomato products compare is essential because tomato-based dishes form the foundation of many cuisines, and the FODMAP content can vary significantly depending on the form and serving size.

Why Are Fresh Tomatoes Low in FODMAPs?

Fresh tomatoes contain small amounts of fructose — one of the monosaccharides in the FODMAP acronym — but at standard serving sizes, the fructose level falls below the threshold that typically triggers symptoms. Tomatoes also contain glucose, which aids fructose absorption in the gut, helping to balance the fructose load.

The issue with tomato products arises when tomatoes are concentrated. Drying, cooking down into paste, or reducing into thick sauces increases the fructose-to-glucose ratio per serving, which can push the FODMAP content above safe thresholds.

FODMAP Breakdown: Tomato Products

Tomato Product	Serving Size	FODMAP Level	FODMAP Type	Notes
Common tomato	1 medium (75g)	Low	Trace fructose	Safe staple
Cherry tomatoes	4 tomatoes (75g)	Low	Trace fructose	Great for snacking
Roma/plum tomatoes	1 medium (75g)	Low	Trace fructose	Good for cooking
Canned tomatoes (diced)	1/2 cup (100g)	Low	Fructose	Keep to standard serve
Tomato paste	2 tablespoons (30g)	Low	Fructose	Moderate at larger serves
Sun-dried tomatoes	2 pieces (4g)	Low	Fructose	High at larger serves
Tomato sauce (plain)	1/2 cup (125g)	Low	Fructose	Check for garlic/onion
Ketchup	1 sachet (13g)	Low	Fructose	Moderate at larger serves

Fresh Tomatoes: Varieties and Serving Sizes

Most fresh tomato varieties are interchangeable from a FODMAP perspective. Whether you prefer beefsteak, Roma, cherry, grape, heirloom, or vine-ripened tomatoes, a standard serving of about 75g is low FODMAP.

Where you might run into trouble is with large servings. A big salad loaded with tomatoes, a caprese stack with thick tomato slices, or a tomato-heavy bruschetta topping could push your fructose intake higher. Aim to keep fresh tomato servings at one medium tomato or equivalent per sitting.

Tomatoes can be enjoyed raw in salads, sliced on sandwiches, or cooked into dishes. The cooking process does not significantly change the FODMAP content of fresh tomatoes — heat does not create or destroy fructose.

Canned Tomatoes: What to Know

Canned tomatoes — including diced, crushed, and whole peeled varieties — are low FODMAP at about 1/2 cup (100g). This is good news for home cooks, since canned tomatoes are the backbone of many pasta sauces, soups, and stews.

Tips for choosing canned tomatoes:

• Select varieties with minimal ingredients (tomatoes, tomato juice, salt, citric acid)
• Avoid canned tomatoes with added garlic, onion, or basil-garlic blends
• Check for added sugar, which increases fructose content
• “No salt added” varieties are fine from a FODMAP standpoint

When building a tomato sauce from canned tomatoes, start with garlic-infused oil as your base instead of sauteing garlic and onion. Add canned tomatoes, salt, Italian herbs (basil, oregano, thyme), and a pinch of sugar to balance acidity. This gives you a flavorful, FODMAP-friendly sauce.

Tomato Paste: Use Sparingly

Tomato paste is highly concentrated — it takes roughly 6 pounds of tomatoes to make 1 pound of paste. This concentration increases the fructose density significantly. Monash University has found tomato paste to be low FODMAP at 2 tablespoons (30g) but moderate at larger servings.

Since most recipes use 1-2 tablespoons of paste diluted into a larger dish, this is usually not a problem. Just be mindful if a recipe calls for a large amount, and consider distributing the dish across multiple servings to keep your per-portion intake reasonable.

Sun-Dried Tomatoes: Proceed With Caution

Sun-dried tomatoes are the most concentrated common tomato product. The dehydration process removes water while retaining all the sugars, resulting in a much higher fructose content per gram. They are low FODMAP at only 2 pieces (about 4g) — essentially a garnish amount.

If you love sun-dried tomatoes, use them as a scattered topping on salads or pasta rather than as a main ingredient. Sun-dried tomatoes packed in oil with garlic are doubly problematic due to the garlic content.

Tomato-Based Sauces: The Hidden FODMAP Trap

The biggest risk with tomatoes is not the tomato itself — it is what gets added to tomato-based sauces and products. Nearly every commercial pasta sauce, pizza sauce, salsa, and tomato soup contains garlic and onion, two of the highest FODMAP ingredients.

Common tomato products with hidden FODMAPs:

• Marinara sauce (garlic, onion)
• Pizza sauce (garlic, onion, sometimes honey)
• Salsa (onion, garlic)
• Tomato soup (onion, cream)
• Barbecue sauce (garlic, onion, honey, high fructose corn syrup)
• Bruschetta topping (garlic, onion)

Scanning products with FODMAPSnap before buying can save you from accidentally choosing a sauce loaded with hidden FODMAP triggers.

Making Your Own Low-FODMAP Tomato Sauce

The safest approach is to make your own sauce. Here is a simple base recipe:

1. Heat 2 tablespoons of garlic-infused olive oil in a saucepan
2. Add 1 can (400g) of diced tomatoes
3. Stir in 1 tablespoon of tomato paste
4. Season with salt, pepper, dried basil, and dried oregano
5. Simmer for 15-20 minutes
6. Add the green tops of spring onions at the end for mild allium flavor

This yields about 4 servings, keeping each portion well within the low-FODMAP range for tomato products.

Tomatoes and Acid Reflux

While not directly a FODMAP issue, many people with IBS also experience acid reflux or gastroesophageal reflux disease (GERD). Tomatoes are acidic and can worsen reflux symptoms in some individuals. If you notice heartburn after eating tomatoes, this is likely an acid-related issue rather than a FODMAP reaction.

Reintroduction of Tomato Products

Fresh tomatoes at standard servings do not need a specific reintroduction challenge since they are low FODMAP. However, if you want to test your tolerance to higher fructose loads from concentrated tomato products, you can gradually increase your serving sizes:

1. Day 1: 2 tablespoons tomato paste in a dish
2. Day 2: 3 tablespoons tomato paste
3. Day 3: 4 tablespoons tomato paste

This tests your fructose tolerance threshold using concentrated tomato as the vehicle.

Key Takeaways

• Fresh tomatoes are low FODMAP at a standard serve of about 75g (1 medium tomato)
• Canned tomatoes are low FODMAP at 1/2 cup (100g)
• Tomato paste is safe at 2 tablespoons (30g) but increases in FODMAPs at larger serves
• Sun-dried tomatoes are only safe at 2 pieces (4g) due to concentrated fructose
• The main risk is garlic and onion in commercial tomato sauces
• Making your own sauce with garlic-infused oil is the safest approach

Related Reading

• Is Garlic Low FODMAP? — The most common trigger hiding in tomato sauces
• Is Onion Low FODMAP? — The other hidden ingredient in pasta sauces
• Is Pasta Low FODMAP? — Pairing tomato sauce with the right noodles
• Is Avocado Low FODMAP? — Another fruit with serving-size considerations

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This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional or registered dietitian before making significant changes to your diet, especially if you have IBS, SIBO, or other gastrointestinal conditions. FODMAP tolerance varies between individuals, and a supervised elimination and reintroduction process is recommended for best results.