“Fibermaxxing” has emerged as a popular nutrition trend on social media, with influencers encouraging individuals to maximize their fiber intake through legumes, whole grains, vegetables, fruits, seeds, and psyllium husk. Although higher-fiber intake is associated with several health benefits, more fiber is not necessarily better. Very high-fiber intake can cause gastrointestinal symptoms and has not been shown to provide proportionately greater benefits.

Nutrition expert and influencer Steph Grasso advocates “fibermaxxing,” a term used to describe maximizing fiber intake or consuming as much fiber as possible.

In an interview with Good Morning America, she said, “Fibermaxxing is slang for eating a ton of fiber and either meeting or exceeding the recommended daily intake.” After years of media coverage focused heavily on protein, Grasso decided to make fiber the focus of her social media content for a year, establishing herself as a prominent fiber influencer.

Abbey Sharp, Maya Feller, and other major nutrition influencers have also recently highlighted the benefits of increasing the intake of legumes, whole grains, vegetables, fruits, seeds, and psyllium husk.

Which health benefits promoted by influencers who advocate “fibermaxxing” are supported by scientific evidence? What is the current evidence for this?

High-Fiber Intake and Mortality

A 2019 systematic review published in The Lancet analyzed nearly 135 million person-years of data from 185 prospective studies and 58 clinical studies. The researchers found that individuals with higher dietary fiber intake had at least a 15% lower risk for all-cause mortality than those with lower intake. For most outcomes, the greatest risk reductions were associated with a daily fiber intake of 25-29 g. Outcomes included all-cause mortality, cardiovascular (CV) mortality, diabetes incidence, and CRC.

In 2013, a systematic review and meta-analysis found that an additional 7 g of dietary fiber consumed per day was associated with a lower risk for CV disease (CVD). Higher-fiber intake was also associated with more favorable low-density lipoprotein cholesterol levels, lower inflammatory markers, a lower risk for myocardial infarction, and a modest reduction in blood pressure.

Numerous meta-analyses have also found an association between higher dietary fiber intake and a lower risk for CRC. Higher-fiber intake has also been linked to greater satiety after meals, lower spontaneous energy intake, and small but consistent reductions in body weight.

High-fiber intake can cause bloating and abdominal pain, particularly with inulin or psyllium husk, or after a sudden increase in daily fiber intake.

Studies have also found that a very high intake of phytate-rich dietary fiber may slightly reduce the absorption of iron, zinc, and calcium. However, there is no evidence that consuming large amounts of fiber-containing dietary supplements, totaling 60-100 g of fiber per day, provides greater health benefits than a typical intake of fiber from natural food sources.

Conclusion

Strong evidence supports the health benefits of a high-fiber diet, including associations with lower all-cause mortality and a reduced risk for CVD. However, most studies have suggested a plateau effect. Increasing daily fiber intake from an insufficient level to approximately 25-35 g/d, depending on sex and the study population, generally provides the greatest health benefits. Further increases appear to provide only modest additional benefits.

From a scientific perspective, fibermaxxing may be reasonable with some limitations. Daily fiber intake should be gradually increased to reduce bloating and other adverse effects. Rather than maximizing fiber intake, the goal should be to reach the recommended daily amount through a varied diet, particularly because most individuals in Germany do not currently consume sufficient fiber.

This story was translated from Univadis Germany, part of the Medscape Professional Network.