Fiber: How Much and What We Should Eat to Prevent Disease

You’ve probably already been told this before, but you should try to get some more fiber in your diet.

No matter the reason why it’s been recommended — even if it’s just to make your daily digestive habits more regular — new research suggests those who consume more fiber are more likely to ward off a whole bunch of diseases.

But this time, it’s not just another study telling you to do one thing this week and the opposite the next.

This research involved 40 years’ worth of information and the World Health Organization, the collective global unit dedicated to making sure we don’t suffer or die prematurely from preventable conditions.

The study looked at past research and found there’s at least one common thread among those who have diets that incorporate more fiber: They’re more likely to live longer and avoid common diseases in the process.

The researchers examined what’s been studied — and found — regarding health outcomes in populations with low to higher than average fiber consumption.

The study, published earlier this week in The Lancet, was a meta-analysis of virtually all studies available in major research databases — and some searched by hand — totaling more than 135 million person years of data. It came from 185 prospective studies and 58 clinical trials with 4,635 adult participants.

Overall, the research over the years pointed to one thing: The population at large is better off consuming more fiber, as it reduces the risk of chronic diseases that are affecting humans en masse.

Those include deaths from any cause and incidences of preventable diseases, such as coronary heart disease, stroke, type 2 diabetes, and colorectal cancer.

How much and what you should eat

Particularly, researchers found that consuming 25 to 29 grams of fiber a day is ideal.

Considering there’s about 5.5 grams of fiber in your average-sized pear and 10 grams in a cup of avocado, that might not seem like a lot. Or a lot if you dislike those foods.

But there are plenty of different high-fiber foods you can incorporate into various parts of your diet. They include fruits such as bananas, apples, and strawberries as well as vegetables like carrots, beets, and artichokes. There’s also lentils, kidney beans, oats, and sweet potatoes.

Even a bowl of popcorn and a few handfuls of almonds while bingeing Netflix can help you fiber-load. But just go easy on the salt (and butter).

It’s these little changes that make a big difference.

In essence, we’d all be a little better off with more fiber in our diets. Or, as the study authors concluded, “Implementation of recommendations to increase dietary fiber intake and to replace refined grains with whole grains is expected to benefit human health.”

The study was funded by the World Health Organization and the Health Research Council of New Zealand, Riddet Centre of Research Excellence, Healthier Lives National Science Challenge, University of Otago, and the Otago Southland Diabetes Research Trust, all out of New Zealand.

New Zealanders, on average, live two years longer than people in the United States. They rank third in the world for adult obesity. The United States is number one.

Optimizing your gut environment

Mindy Haar, PhD, assistant dean of undergraduate affairs at the New York Institute of Technology School of Health Professions, agrees with the study’s findings.

She says it’s backed by a “plethora” of other research that demonstrates the long-term effects of fiber-rich diets.

“In the past few years, increasing attention has been on the microbiome, the intestinal flora,” Haar told Healthline. “Fiber acts as a prebiotic, boosting the proliferation of probiotics in the intestine. There are many kinds of probiotics that promote good health, so consuming a variety of high-fiber foods optimizes the gut environment.”

Haar says those foods include fresh fruits and vegetables, whole-grain breads, cereals, pastas, brown rice, quinoa, beans, and chickpeas.

If the study’s findings suddenly inspire you to start bingeing fiber, Catherine Brennan, a registered dietitian nutritionist who writes for FeelingFullNutrition.com, would like you to know a few things.

The first is to think twice before reaching for fiber supplements. (The recent study purposely didn’t include them in their research.)

“Fiber is naturally abundant in nutritious foods, which trump supplements every time,” Brennan told Healthline. “Some studies have found that fibers found in food can be more beneficial than supplements, such as helping us feel satiated and satisfied after a meal.”

If you’re going to start adding fiber to your diet, Brennan recommends doing it gradually and with plenty of water. Fiber works as a sponge as it digests, so it needs more water to pass through smoothly.

You’ll also more likely fill up quicker during a meal, which could cause discomfort and possibly flatulence.

“Aim to slow down at mealtimes,” Brennan said, “and pay attention to your fullness cues to avoid discomfort.”