The Late Paleolithic diet carried around 45 grams of fibre a day, mostly without trying. Modern Australian intake sits closer to 18. The food hasn't disappeared. The fibre has. Wheat gets milled to strip the bran, fruit has been bred for sweetness over substance, and most vegetables are peeled and processed before they reach you. Even eating "healthy" in 2026 puts you well below what your gut bacteria evolved to expect.

The Hadza of Tanzania are one of the last hunter-gatherer populations on earth. They eat around 100 grams of fibre a day from tubers, berries and baobab fruit. Sequencing of their gut microbiomes has found more than 700 microbial species, roughly 40% more bacterial diversity than the average industrialised gut, including dozens of species the rest of us have simply lost. The Hadza aren't built differently to anyone reading this. They eat in a way that feeds the same bacteria all of us are carrying.

A probiotic delivers bacteria but doesn't feed them, most strains don't survive the stomach acid, and the few that reach the colon need fibre to settle in. With nothing waiting for them they pass through and leave. You can take a probiotic every day for a year and barely move the needle, because every shipment is arriving with nowhere to stay.

Carnivore, keto, low-FODMAP, low-carb, gluten-free. Each one removes a category of food, and most of them remove fibre with it. The bacteria don't care what symptom you're trying to fix; they go hungrier regardless. One controlled trial published in the Journal of Nutrition found four weeks on a strict low-FODMAP diet cut Bifidobacteria populations by close to half. Carnivore takes fibre intake to zero by definition. People often feel briefly better because something irritating is gone, then quietly worse three months in once the microbiome has thinned out.

Fibes pairs ten grams of fibre per serve with four sources, each chosen for the role it plays in your gut. Sunfiber® PHGG, a soluble fibre tolerated well enough that hospitals use it in clinical nutrition, with research behind it on digestive comfort. Tapioca resistant starch, which behaves more like a fibre than a starch, passing the small intestine intact and reaching parts of the lower bowel the other three don't. Soluble corn fibre, tolerated at doses most fibres can't touch, with clinical work behind it on a steadier post-meal response. Actazin® green NZ kiwifruit, a cold-pressed concentrate carrying both fibre and actinidin, the kiwifruit-only enzyme that supports protein digestion, with clinical research behind it on bowel regularity. Most users see results inside the first week, and they hold for as long as you keep at it. Month two adds the rhythm of going regularly without thinking about it, and by month three most people are settled into a daily regularity they'd long given up on.