Based on your daily energy intake.
What does fibre intake mean?
Dietary fibre is the indigestible portion of plant foods, carbohydrates that pass through the digestive system without being fully broken down and absorbed. It falls into two main categories: soluble fibre (which dissolves in water and forms a gel-like substance) and insoluble fibre (which adds bulk to stool and speeds transit through the gut).
The Dietary Guidelines for Americans 2020–2025 recommend 14 grams of fibre per 1,000 calories consumed. This energy-based recommendation accounts for the fact that larger people eat more food and therefore more fibre, while the ratio between fibre needs and energy intake remains relatively constant. At a typical 2,000 kcal/day diet, this translates to 28 grams per day.
Despite the clear evidence for fibre's benefits, surveys consistently show that most adults in Western countries consume only 15–18 grams per day, roughly half the recommended amount. This "fibre gap" is linked to population-level increases in cardiovascular disease, type 2 diabetes, colorectal cancer, and gut dysbiosis.
Soluble fibre, found in oats, barley, apples, legumes, and psyllium, is particularly effective at lowering LDL cholesterol by binding bile acids in the gut and preventing their reabsorption. Prebiotic fibres such as inulin (from chicory, garlic, onions) selectively feed beneficial Bifidobacterium and Lactobacillus species in the colon, supporting immune function and reducing gut permeability.
Reference ranges
| Daily calorie intake | Fibre target (g/day) |
|---|---|
| 1,500 kcal | 21 |
| 2,000 kcal | 28 |
| 2,500 kcal | 35 |
| 3,000 kcal | 42 |
| 3,500 kcal | 49 |
When should you see a doctor?
Most people can safely increase fibre intake by gradually adding more whole plant foods. Increase fibre slowly (over several weeks) and drink plenty of water to avoid bloating, gas, and discomfort. If you have inflammatory bowel disease, intestinal strictures, or a recent bowel surgery, consult a gastroenterologist or dietitian before significantly increasing dietary fibre, as high-fibre diets can worsen symptoms in some conditions.