How Fiber First works

Three numbers, real research, and a plant library you can trust. Here's exactly how it works — and where every number comes from.

Three numbers that matter

Fiber First measures the three things that actually shape gut health. No calories, no grades — just these.

Fiber — the fuel your gut bacteria feed on, and where feeling good starts. More than 9 in 10 adults fall short. The average person eats just 10–15g of fiber a day — under the ~30g most health guidelines call a minimum, and far below the 40g that research links to a genuinely diverse, thriving gut. That's the gap Fiber First is built to close.

Plant variety — different plants feed different microbes, so diversity matters as much as amount. The more variety you eat, the healthier your gut — and since around 70% of your immune system lives there, the stronger your immune system is, too. The goal: 30 different plants a week.

Hydration — fiber needs water to do its work. Without enough water, more fiber can backfire; with it, everything moves the way it should. We count every fluid, food and drinks together, so the picture's complete.

Together they roll into one daily Gut Score out of 100 — a single number that tells you how well you fed your gut today.

The research behind it

30 plants a week comes from the American Gut Project — an analysis of more than 10,000 microbiome samples across the US, UK, and Australia. People who eat 30+ different plants a week have significantly more diverse gut microbiomes than people eating fewer than ten.
40g of fiber a day is rooted in research on what supports microbial diversity — well above the 10–15g most people actually get.
Plant variety and hydration round out the picture, because fiber works best alongside a wide range of plants and enough water.

Where our food data comes from

USDA FoodData Central is our primary source for whole-plant foods — the fiber and water content per 100g that Fiber First runs on.
Peer-reviewed research fills the gaps for foods USDA doesn't cover well, like sea vegetables, sprouts, and microgreens.
Every food is hand-curated. We match each one to a specific verified entry — no fuzzy auto-matching — and keep its source on record.
The plant library stays current. It's reviewed regularly, and foods you request get added on a rolling basis.

We keep Fiber First focused on the three things that move gut health — no calorie counting, no per-food grading, no noise.

Common questions

Why doesn't Fiber First track animal products?

Animal products contain zero dietary fiber — meat, dairy, eggs, and fish have none; that's a biochemical fact. Fiber First is built around three evidence-based predictors of gut health: fiber intake, plant variety, and hydration. Animal products don't contribute to either fiber intake or plant variety, so they aren't part of the plant library.

Does dehydrating food remove fiber?

For fiber tracking, the drying method (dehydrator, oven, sun, freeze-dry) makes only a small difference per 100g — typically within 10%, varying by food; final moisture content matters more. Across all these methods, fiber stays largely intact. Low-temperature dehydration also preserves more enzymes and heat-sensitive nutrients — any choice that keeps more of the food's living quality is one to celebrate.

What does "dried" mean in the plant library?

It's our umbrella term for any food with the water removed (dehydrator, oven, sun, freeze-dry). One label keeps the plant library simple to search, and since the method makes only a small difference to fiber, a single label covers every form cleanly.