If you have IBS, you already know the routine. You try a protein powder, follow the instructions, and within an hour you're dealing with bloating, cramping, or a sudden dash to the bathroom. You blame your gut. You wonder if protein supplementation is simply off the table for you.
It isn't. The problem, in most cases, is not your gut — it's what's in the powder.
IBS affects up to one in five people in the UK, and those figures likely underrepresent the real number given how many people never receive a formal diagnosis. For people managing the condition through diet — including those following a low FODMAP protocol — finding a protein powder that doesn't trigger symptoms has, until recently, been close to impossible. Most mainstream options are full of the very compounds that make IBS worse. Understanding why is the first step to choosing better.
Why Most Protein Powders Are Bad for IBS
The protein itself is rarely the whole story. What surrounds it — the sweeteners, fillers, thickeners, and added fibres — is usually where the trouble starts.
Whey protein and lactose
Whey is derived from milk. Even in its concentrated form, it retains lactose — the disaccharide that people with IBS frequently struggle to tolerate. Lactose is a FODMAP (more on that shortly), and when it reaches the large intestine undigested, gut bacteria ferment it, producing gas, bloating, and urgency. Whey isolate contains less lactose than whey concentrate, but it still comes from a dairy source and remains unsuitable for many IBS sufferers.
Artificial sweeteners — sorbitol, sucralose, and others
Many protein powders are sweetened with polyols like sorbitol or maltitol, or with synthetic sweeteners such as sucralose and aspartame. Polyols are a direct FODMAP category — they are poorly absorbed in the small intestine and ferment in the colon. Even sweeteners that aren't technically FODMAPs, like sucralose, can alter gut motility and microbiome composition in ways that exacerbate IBS symptoms in sensitive individuals.
Gums — xanthan, guar, and carrageenan
Xanthan gum and guar gum appear on ingredient lists across the supplement industry. While laboratory testing by FODMAP Friendly confirms both are low FODMAP at typical serving sizes, they are fermentable fibres and can contribute to gas production in people with a particularly sensitive gut. Carrageenan — a seaweed-derived thickener common in ready-to-mix protein shakes — has been associated with gut inflammation in animal and in vitro studies.
Inulin and chicory root
This is perhaps the most hidden FODMAP trigger in protein powders. Inulin, which is also sold under the names chicory root, chicory fibre, and chicory extract, is a fructan — a high-FODMAP carbohydrate. It is added to protein powders to boost fibre content and improve texture, but even 0.5 to 1 gram can cause gas, bloating, abdominal pain and diarrhoea in people with IBS. If a protein powder proudly declares it "contains prebiotics" or "supports gut health," check the ingredients list: inulin is often what they mean.
What to Look for in an IBS-Safe Protein Powder
When choosing a protein powder that won't aggravate IBS, use this checklist as your guide:
- FODMAP Friendly certified — not self-declared "low FODMAP," but independently laboratory-tested and certified by FODMAP Friendly
- No artificial sweeteners — avoid sorbitol, mannitol, xylitol, maltitol, sucralose, aspartame
- No added inulin or chicory root — check for "chicory fibre," "chicory extract," or "prebiotic fibre" on the label
- No added gums beyond trace levels — particularly carrageenan
- Plant-based — avoids the lactose inherent to dairy-derived proteins
- Minimal ingredients — the shorter the list, the less there is to trigger a reaction
- Transparent labelling — no hiding behind "natural flavours" or vague "protein blend"
The UK's Only FODMAP Friendly Certified Protein Food
That Protein was founded with one guiding principle: real food ingredients, no additives, nothing that doesn't need to be there. Founded by Patrick Mooney, the brand occupies a genuinely distinct position in the UK market — not as a supplement company, but as a premium food brand that takes gut health seriously.
Two That Protein products hold full FODMAP Friendly certification: Blissful Brown Rice & Raw Cacao and Double Choc Protein Porridge. This is not a self-declaration or a marketing claim. FODMAP Friendly certification — awarded by fodmapfriendly.com, the world's first low FODMAP certification body — requires independent laboratory testing of the finished product in a NATA and ISO-accredited lab. Every batch must meet strict FODMAP thresholds before the certification seal can be used.
Tim Mottin, director of the FODMAP Friendly Food Programme, confirmed at the time of That Protein's certification that it was "the first protein powder product to be certified in the UK under our certification program." That status has not changed.
For anyone following a low FODMAP elimination phase or managing IBS through diet, this certification provides a level of assurance that no amount of "gut-friendly" marketing copy can replicate. The product has been tested. The results are on record.
Which That Protein Product is Right for You?
Blissful Brown Rice & Raw Cacao — 250g, £19.99
Two ingredients: organic brown rice protein and organic raw cacao. FODMAP Friendly certified. Fourteen grams of protein per 25g serving with 55g protein per 100g. No sweeteners, no gums, no additives. The cleanest option for those in the strict elimination phase of a low FODMAP diet or with multiple food sensitivities.
Double Choc Protein Porridge — 600g, £19.99
Made with organic oats, plant protein, raw cacao, cacao nibs, and palmyra nectar. FODMAP Friendly certified. Designed for those who want a more substantial breakfast that still supports gut health. Suitable for IBS and sensitive stomachs.
Chirpy Chirpy Choca Mocha — 250g, £19.99
Organic brown rice protein, organic raw cacao, and organic coffee. Fourteen grams of protein per 30g serving. Low FODMAP and additive-free. FODMAP Friendly certification pending.
Nutty Nutty Peanut Butter — 300g, £19.99
Roasted peanuts and peanut protein powder. Fourteen grams of protein per 30g serving. FODMAP Friendly certification pending.
Perfectly Pure Plant Porridge — 600g, £19.99
Gluten-free oats and pumpkin seed protein powder. Twenty grams of protein per 60g serving. Unflavoured. FODMAP Friendly certification pending.
What About Whey?
Whey protein remains the dominant force in the UK protein market. It is affordable, widely available, and well-studied for muscle protein synthesis. But for people with IBS, it carries several problems beyond lactose.
First, even whey isolate — which has had most of the lactose filtered out — is still derived from dairy. For the significant overlap between IBS sufferers and those with lactose sensitivity (lactose is a FODMAP disaccharide), even trace quantities can be enough to trigger symptoms during an elimination phase.
Second, mainstream whey products are almost universally formulated with artificial sweeteners, flavour compounds, and thickeners. These additives — not found in plain, unsweetened whey — are where the FODMAP and gut-reactivity burden often sits in commercial products.
Third, there is the protein itself. Whey is rapidly digested, and when consumed in large quantities, any undigested protein that reaches the colon is fermented by gut bacteria. For people with an already reactive digestive system, this can compound the symptoms caused by the additives.
Switching to a plant-based protein that has been independently verified as low FODMAP removes several of these variables at once.
Frequently Asked Questions
Q: Can I use a protein powder if I have IBS?
Yes — but the choice of protein matters significantly. Most mainstream protein powders contain ingredients that are known FODMAP triggers. A protein powder that has been independently FODMAP Friendly certified and contains no artificial sweeteners or added gums is appropriate for most people managing IBS through diet.
Q: Is pea protein low FODMAP?
Pea protein isolate is generally considered low FODMAP, as processing removes most of the galacto-oligosaccharides (GOS) present in whole peas. Monash University and independent researchers have confirmed that the processing of pea protein isolate reduces its FODMAP content substantially.
Q: What does "FODMAP Friendly certified" actually mean?
FODMAP Friendly is the world's first low FODMAP certification programme, established in 2012. Certification requires that a finished product is independently tested in a NATA and ISO-accredited laboratory and confirmed to contain FODMAPs below established threshold levels. You can verify certified products at fodmapfriendly.com.
Q: Is plant protein better for IBS than whey?
Plant protein does not inherently contain lactose and, when sourced from clean, additive-free products, eliminates several of the most common FODMAP triggers found in dairy-based proteins.
Find the Right Protein for Your Gut
If you're managing IBS or following a low FODMAP diet and have been unable to find a protein powder that works for you, the range at That Protein was built with precisely this gap in mind. Every product is additive-free and made with organic ingredients. Two are fully FODMAP Friendly certified. None contain artificial sweeteners, gums, or hidden FODMAP triggers.
Browse the full range at thatprotein.com/collections/all.