How Much Fiber Should We Consume?

A new meta-analysis reviewing the past 40 years of research examined how much fiber we should consume to prevent chronic diseases and premature death.

Researchers, public health bodies, doctors, and dietitians have long described fiber’s benefits, but “Exactly how much fiber should we consume?” is difficult to answer clearly. This prompted the World Health Organization (DSÖ) to launch a study, with results published in Lancet . It identified which carbohydrates best protect against non-communicable diseases and help weight loss . These diseases are also called chronic diseases and generally last long and progress slowly. The DSÖ identifies “four types”: cardiovascular diseases, cancer, chronic respiratory diseases, and diabetes.

Daily Intake of 25–29 Grams of Fiber Is Ideal

Reynolds and colleagues reviewed observational data (135 million person-years) and, involving more than 4.600 people, 58 clinical trials . Studies spanning almost 40 years were analyzed for chronic disease incidence and premature mortality. These included coronary heart disease, cardiovascular disease, stroke, type 2 diabetes, colon, breast, endometrial (uterine), esophageal, and prostate cancer, and various obesity-related cancers.

Overall, high-fiber consumers had %15–30 lower risk of premature death from any cause or cardiovascular conditions than low-fiber consumers. Fiber-rich foods reduced coronary heart disease, stroke, type 2 diabetes, and colon cancer risk by 16–24 percent.

Which Foods Are Rich in Fiber?

Fiber-rich foods include whole grains, vegetables, fruit, and legumes such as peas, beans, lentils, and chickpeas. The analysis identified beneficial daily intake as 25-29 grams (g). Many developed-country populations consume much less (averaging around 15 grams daily). Researchers suggest more than 29 g daily may yield greater benefits. Although fiber has no adverse health effects, very high intake may harm people with iron or mineral deficiency. Iron deficiency may worsen in people eating excessive bran-rich foods. Clinical trials also showed a strong association between more fiber, lower weight, and lower cholesterol.

Why Is Fiber So Good for Health?

Research has explored fiber’s health benefits, chemistry, physical properties, physiology, and metabolic effects for more than 100 years. Fiber-rich foods provide fullness, aid weight loss/control, and may improve lipid and glucose levels. Fiber breakdown in the large intestine by microbiota (resident bacteria) has wide-ranging effects, including colorectal cancer protection.

These findings provide compelling evidence for guidelines emphasizing more dietary fiber and replacing refined grains with whole grains. Higher-fiber diets reduce many chronic diseases and related mortality.

Fiber amounts in some fiber-rich foods: