Low FODMAP Calculator

Yes, tomatoes are generally considered low FODMAP at a standard serving of around 65 g (about one medium tomato). However, larger servings can push fructose levels higher, making them moderate to high FODMAP. Cherry tomatoes have a slightly different threshold, so portion control matters.

The low FODMAP diet does not cure IBS, but it is one of the most evidence-based dietary strategies for managing IBS symptoms. Research from Monash University shows that around 75% of IBS patients experience significant symptom relief during the elimination phase. It is best used as a structured three-phase protocol under the guidance of a registered dietitian.

Some people experience a temporary worsening of symptoms in the first few days as the gut microbiome adjusts to the reduced fermentable fibre intake. This is normal and typically resolves within a week. Make sure you are not inadvertently consuming hidden FODMAPs in processed foods, sauces, or seasonings.

The low FODMAP diet is not inherently high in protein, but many protein sources — such as plain meats, fish, eggs, and firm tofu — are naturally very low in FODMAPs. You can structure a high-protein low FODMAP plan, but it requires careful selection of plant proteins since many legumes are high FODMAP in large portions.

The low FODMAP diet is commonly used alongside SIBO (Small Intestinal Bacterial Overgrowth) treatment to reduce symptoms like bloating and abdominal pain by limiting the fermentable carbohydrates that feed bacterial overgrowth. However, it does not eradicate SIBO on its own — antibiotic or herbal antimicrobial protocols are typically needed as the primary treatment.

Low FODMAP foods are easier to digest for people with IBS or other functional gut disorders because they contain fewer short-chain carbohydrates that ferment rapidly in the large intestine. For people without gut sensitivity, high FODMAP foods like garlic, onion, and legumes are perfectly healthy and support a diverse gut microbiome.

Certain probiotic strains, particularly Lactobacillus and Bifidobacterium species, have shown benefit for IBS symptoms in clinical studies. During the low FODMAP elimination phase, probiotics may help support the gut microbiome, which can be reduced by the lower fibre intake. Look for probiotic supplements without added high FODMAP prebiotic fibres like inulin or FOS.

The traffic light system — originally developed by Monash University — uses green (low FODMAP, safe to eat), amber (moderate FODMAP, eat with caution), and red (high FODMAP, avoid during elimination) to categorise foods. Ratings depend on both the type of FODMAP present and the serving size, which is why portion control is a core part of the diet.