Still Bloated on a Plant-Based Diet? Here’s Why Your Gut Might Be Struggling

You’re drinking the green juice, you’re saying yes to lentils, you’re lovingly massaging your kale…
So why does your belly still feel like it’s five months pregnant by lunchtime?

If you’ve switched to a colourful, fibre-rich, plant-powered way of eating, and yet you’re still battling bloating, cramping, reflux or chaotic bowel habits, you’re not alone. And no, you’re not failing at wellness.

As a naturopath specialising in plant-based nutrition, I work with people who have committed to eating more whole plant foods—for their health, the planet, or both—but their digestion hasn’t quite caught up. Maybe you’ve been told you have “IBS”. Maybe you’ve been advised to just cut out gluten. Or maybe you’ve started to wonder if your gut just can’t cope with this plant-based lifestyle.

Here’s the truth: your body isn’t broken, and your diet probably isn’t the problem. But there may be something else going on, something I’ve found through my clinical experience to be fairly common, particularly among health-conscious plant-based eaters: SIBO.

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Meet the Likely Culprit: SIBO (Small Intestinal Bacterial Overgrowth)

SIBO is a condition where bacteria that belong in the large intestine end up growing in the small intestine instead, where they cause chaos. It’s now understood to be one of the most common underlying causes of IBS symptoms, especially when bloating hits hard and fast after meals.

These displaced bacteria love fermenting your fibre before your body’s ready. And while that fermentation process is typically brilliant in the colon—where it supports short-chain fatty acids and immune health—in the small intestine it creates… well, gas. And pressure. And sometimes nausea, reflux, diarrhoea, or constipation. Sometimes all of the above, depending on the day and the microbes in charge.

Classic SIBO Symptoms Include:

• A bloated belly that usually gets worse as the day goes on
• Cramping, gurgling, or discomfort after meals
• Reflux, burping, or nausea
• Loose stools, constipation, or alternating between both
• Fatigue, brain fog, and poor concentration
• Skin issues, like acne or rashes
• Mood changes, irritability, or even depression
• Nutrient deficiencies, especially iron and B12

It’s not just a “sensitive gut.” It’s a real microbial imbalance—and it’s fully treatable.

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Why It’s So Common in Plant-Based Eaters

I see this all the time in clinic: someone has chosen a plant-based or vegan lifestyle—maybe for health, maybe for animals, maybe because, arguably, tofu tastes surprisingly great—but their digestion isn’t thriving.

Here’s why that might be happening:

• High-fibre diets can overwhelm a compromised gut: When the migrating motor complex (the gut’s housekeeping wave) isn’t doing its job properly, fibre ferments in the wrong place. Think of it like a dinner party where the guests arrived before the host had finished tidying. It gets messy.
• Post-antibiotics or food poisoning: These events can damage the gut’s natural balance and allow bacteria to overstay their welcome in the small intestine.
• A history of restrictive diets or eating disorders: Sadly, these can alter gut motility and bacterial balance long-term.
• Chronic stress or trauma: The gut-brain axis is real, and stress affects motility more than we often realise. Even “good stress” (hello, overachievers) can easily throw digestion off.
• Low stomach acid from medications like PPIs: These make it easier for unwanted bacteria to survive the journey into the small intestine.

These are not the only contributors; underlying conditions like hypothyroidism are also a common contributor.  It’s important not just to address the SIBO, but also work with an experienced clinician to help identify and address the contributing factors.

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SIBO vs IBS: What’s the Difference?

Here’s the kicker: many people diagnosed with IBS actually have SIBO.
Let’s break it down:

• IBS-D (diarrhoea dominant) is often linked to hydrogen-producing bacteria
• IBS-C (constipation dominant) is frequently driven by methane-producing organisms (technically archaea, not bacteria, but let’s not split microbial hairs)
• Mixed-type or “strange” cases may involve hydrogen sulphide, a less common but increasingly recognised gas, which thankfully tends to be less common in plant-based eaters.

SIBO can’t be diagnosed just by symptoms—you’ll need a breath test through a practitioner who knows how to interpret the results properly (hint: that could be me). But once you’ve got clarity, treatment can be incredibly effective.

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So… Do You Have to Give Up Fibre?

No. Please don’t panic and throw your lentils out the window.

You might need a short-term strategy that gently reduces fermentable fibres (like a modified plant-based version of a low-FODMAP or SIBO-specific diet), but the long-term goal is always rebuilding resilience—so you can enjoy fibre again without fear.

Healing from SIBO isn’t just about starving bacteria. It’s about restoring rhythm to your gut, calming inflammation, balancing your nervous system, and rebuilding the strength of your microbiome without sacrificing the ethics or nourishment of a plant-aligned way of eating.

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What You Can Do Next

1. Track your symptoms – Notice when the bloating starts. Is it 30 minutes after a smoothie? Two hours after a meal? Patterns can offer clues.
2. Don’t self-diagnose – Bloating doesn’t automatically equal SIBO. But if you’ve had IBS for years with no real improvement, testing is worth considering.
3. Work with someone who gets it – Especially if you’re plant-based. You don’t need to be told to eat fish or bone broth to fix your gut. There are better, kinder, and highly effective ways.
4. Address nervous system health – Somatic practices, trauma resolution, and nervous system support can profoundly impact motility and healing.  I love using a method called Rapid Core Healing with my SIBO clients.

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Bottom Line

If you’re eating the rainbow but feeling more like a hot-air balloon, don’t give up on your values—or your gut. You’re not doing it wrong. Your body may just need a little extra guidance to find its rhythm again.

SIBO is common, confusing, and frustrating—but it’s also manageable. With the right support, you can get back to feeling energised, clear, and comfortable in your body.