Fiber
The longevity nutrient hiding in plain sight.
~95% of Americans do not meet the recommended fiber intake
Why it matters for longevity
Dietary fiber feeds beneficial gut bacteria, regulates blood sugar, lowers cholesterol, and promotes healthy bowel function. A landmark meta-analysis in The Lancet found that people eating 25-29g of fiber daily had a 15-30% lower risk of all-cause mortality, heart disease, stroke, type 2 diabetes, and colorectal cancer compared to low-fiber diets. Every 8g increase in daily fiber was linked to a 5-27% reduction in these conditions.
How much you need
38g for men, 25g for women (adequate intake)
Longevity researchers suggest 30-50g daily, closer to what ancestral diets provided.
Signs you might be low
- Constipation or irregular bowel movements
- Blood sugar spikes after meals
- Feeling hungry soon after eating
- High LDL cholesterol
Best food sources
Key research
Reynolds A et al. (2019). Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. The Lancet, 393(10170), 434-445.
Track your fiber with Biohack
Every meal scored for longevity. 23 nutrients tracked automatically. AI coaching to close your gaps.
Related articles
What Centenarians Actually Eat (And What They Skip)
We studied the diets of people who live past 100. The patterns are surprisingly simple, and most modern diets get them wrong.
What Blue Zone Diets Have in Common (It Is Not What You Think)
Five regions, five different cultures, one pattern. The shared thread across Blue Zone diets is not a single food group.