You need 50+ grams of fiber per day for optimal health
evidence
The Claim
Some health advocates and ancestral diet proponents claim modern humans should eat 50-100g of fiber daily, based on estimates of prehistoric diets.
Origin
Studies of hunter-gatherer diets estimated fiber intakes of 50-100g/day. This led some to argue that modern recommendations of 25-38g are too low. Paleo and ancestral health communities popularized this idea.
What Science Says
While higher fiber intake is generally beneficial, evidence supports the 25-38g/day recommendation as the threshold for most health benefits. The Lancet meta-analysis (2019) found the greatest risk reduction for cardiovascular disease and diabetes at 25-29g/day, with diminishing returns above 30g. Very high intakes (>70g) can cause GI distress and may impair mineral absorption. The 25-38g target is evidence-based and sufficient for most people.
Verdict
Misleading
Sources
- PMID:35816465 The Effect of Fiber Supplementation on Chronic Constipation in Adults: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials.
- PMID:37078654 Effects of dietary fibers or probiotics on functional constipation symptoms and roles of gut microbiota: a double-blinded randomized placebo trial.