The headline numbers
NHMRC's Adequate Intake (AI) for dietary fibre is 30g a day for men and 25g a day for women. Only 28.2% of Australian adults meet it (27.9% of women, 28.5% of men). NHMRC's higher benchmark, the Suggested Dietary Target (SDT), is 38g a day for men and 28g a day for women, the level NHMRC associates with reducing risk of diet-related disease. Only 17.0% of adults meet that (19.9% of women, 14.0% of men).
Younger adults fall shortest
Age matters more than most people would guess. Among adults, 19 to 30 year olds are the age group least likely to meet the Suggested Dietary Target. The pattern is sharper again in children and teenagers: 58.4% of 2 to 3 year olds meet the Adequate Intake, against just 29.4% of 14 to 18 year olds. A 2 to 3 year old is roughly 39 times more likely to meet the Adequate Intake than a 14 to 18 year old.
Income and fibre intake move together
There's a consistent gradient by socioeconomic status (SES), measured in quintiles from lowest to highest. Among adults, 24.2% of people in the lowest SES quintile meet the Adequate Intake, compared with 32.7% in the highest quintile. Each step up in SES quintile is associated with a 9% increase in the likelihood of meeting the Adequate Intake. The same pattern is even stronger in children: each step up in SES quintile is associated with a 20% increase in the likelihood of meeting the Adequate Intake, with the lowest-SES children at 33.3% and the highest-SES children at 51.1%.
The fibre gap isn't just a matter of individual choice. It tracks age and income closely enough that it behaves like a structural pattern, not a random one.
Sources
- Fayet-Moore F, et al., "Dietary Fibre Intake in Australia. Paper I: Associations with Demographic, Socio-Economic, and Anthropometric Factors," Nutrients, 2018, PMC
- NHMRC, Nutrient Reference Values for Australia and New Zealand Including Recommended Dietary Intakes
- ABS, Food and Nutrients, 2023