No doubt you’ve heard you need to eat more fiber, but are you? A whopping 95 percent of Americans aren’t getting enough, according to a study from the American Journal of Lifestyle Medicine. While dietary guidelines call for women to get at least 25 grams of fiber and men 38 grams, the average American eats only about 14 or 15 grams.
Numerous reasons may be at play for America’s fiber deficit. Along with being hyper-focused on protein, which sometimes results in less vegetables on the plate, people are often unaware where fiber comes from — thinking it’s found in meat, seafood and dairy. To set the record straight, though, “meat, eggs and dairy contain zero fiber,” says Nichole Dandrea-Russert, MS, RD, registered dietitian nutritionist in Atlanta and author of The Fiber Effect (Hatherleigh Press, 2021). “Plants are where you’ll find your fiber.”
Still not sure why fiber is crucial to health? Here are 10 reasons that ought to convince you why you need to eat more of it:
1. You’ll Build a Healthier Gut
What you eat determines which bacteria are able to thrive in your gut, which matters because 70 percent of your immune system is housed in your gut and can influence inflammation. “Research tells us that good bacteria get stronger when fed colorful, fibrous plant-based foods,” says Dandrea-Russert, citing a study that found that vegetables, fruits and whole grains fed good bacteria, while meat, dairy, eggs, and processed food fostered an unbalanced gut microbiota.
The best way to eat for your gut? Eat a wide variety of plants. “The more diverse the amount of plants you eat, the most diverse the amount of bacteria in your gut,” she adds. That leads to a thicker mucous wall and intestinal barrier, lowering inflammation and leading to better digestion and overall health.
2. You’ll Have Better Heart Health
Women often think that breast cancer is their No. 1 killer, when it’s actually heart disease. And fiber’s ability to reduce cardiovascular disease is well-documented, with studies showing that fiber can lower cholesterol and blood pressure.
“Fiber binds to cholesterol and helps eliminate it from the body,” explains Tanya Zuckerbrot, MS, RD, CEO and founder of F-Factor and author of The F-Factor Diet (TarcherPerigee, 2007). In fact, in one study from Tulane University, eating 7.2 to 18.9 grams of fiber a day lowered systolic (the top number) and diastolic (the bottom number) blood pressure.
3. You’ll Eliminate Toxins
While it’s true that water will help flush out toxins you’re exposed to during the day, fiber is also key. “Fiber absorbs water and expands, and when it does, it will push toxins through your digestive tract,” Zuckerbrot says. Without enough fiber, though, those toxins can stick to your colon, rectum and anus and become carcinogenic, she adds. You should be going number two at least once a day.
4. Your Brain Will Get a Boost
There’s a well-documented link between your gut and your brain, and when you eat fiber, you’re giving the good bacteria in your gut the food it loves to munch on. The upshot? “When you feed the gut microbiota a fiber-rich diet, it will produce short-chain fatty acids, namely one called butyrate, which plays an important role in brain health,” Zuckerbrot says. “Butyrate helps create new brain cells and protects brain neurons from cell death, which affects Parkinson’s disease and dementia, and it has a profound impact on improving memory and learning.”
5. You’ll Ward Off Depression
In a study in the journal Menopause, premenopausal menstruators who increased their fiber intake experienced a decrease in depression prevalence. Just 1 gram of additional fiber per every 1,000 calories resulted in a 5 percent decrease in depression prevalence.
6. Your Fitness Will Improve
There are three ways fiber can aid athletes of all levels. For starters, you’ll have better recovery with enough fiber on board. “Because fiber fosters a healthy gut and a healthy gut reduces local and systemic inflammation, many athletes report improved recovery after training,” says Dandrea-Russert, adding that this not only helps with recovery from the previous training session but also allows for better performance in future training sessions.
Second, you’ll spend less time being sick, and this is key because endurance athletes may be at higher risk for respiratory infections. “Because the majority of the immune system resides in the gut, you can expect a more robust immune system when you swap high-fiber plant foods for meat and dairy products,” she says. Plus, if you do get sick, those fiber-packed plant foods may prevent and shorten the duration of respiratory illnesses. Finally, eating more fiber and less processed foods can improve sleep, which will improve your physical and mental performance.
7. You’ll Lower Your Risk of Cancer, Especially Breast Cancer
One of the best things about fiber is its sponge-like property. Not only does it absorb things like cholesterol, but it also can soak up hormones like estrogen. “Elevated levels of estrogen are known to cause an increased risk for breast cancer, but fiber can help pull estrogen out of the body,” Zuckerbrot says. In fact, the earlier you start eating more fiber, the better. A study from the journal Pediatrics found that high amounts of fiber during adolescence and early adulthood were associated with a 16 percent lower overall risk of breast cancer and 24 percent decreased risk before menopause.
8. You’ll Naturally Lose Weight
Just by eating more fiber, you might shed weight? It sounds too good to be true, but it’s not. Soluble fiber slows digestion and absorption of a meal, but that’s not all. “It also adds bulk to meals without adding calories,” Dandrea-Russert says. Why does that matter? “You’ll be satiated more quickly than a meal without adequate fiber, keeping you full longer, which may influence how much you eat as well as the timing and choices of your next meal.” As if that’s not enough reason to load up on fiber, fiber also fuels healthy bacteria in your gut, and research has shown that inadequate fiber may fuel inflammation, which has been associated with weight gain.
9. You’ll Control Blood Sugar and Lower Your Risk of Diabetes
When your blood sugar isn’t stable, you’ll be more prone to mood swings, depression and anxiety — not to mention, of course, that you’ll increase your risk of diabetes. Yet with enough fiber, you can control that blood sugar. “Fiber slows the absorption of sugar from food into the bloodstream, preventing spikes in blood sugar,” Dandrea-Russert explains. And because it helps create a healthier gut, that will increase insulin sensitivity and help direct blood sugar into cells where it belongs versus circulating in your bloodstream.
10. You’ll Be Adding Valuable Nutrients to Your Diet
The only way you can consume more is by eating more plant-based foods. Because plants aren’t only loaded with fiber but also phytonutrients, essentially nutrients found only in plant foods, you’ll be adding them to your diet, too. “The phytonutrients that accompany fiber also come with myriad benefits like brain health, skin health, gut health and more,” Dandrea-Russert says.
Ready to chomp more fiber? Just start slowly to prevent gastrointestinal discomfort, says Dandrea-Russert, suggesting that you add 5 to 10 grams a week to let your body adjust. And don’t forget to drink lots of water. Just don’t worry if you have an increase in gas, which is a normal reaction to adding fiber-rich foods. “That’s the good bacteria going to work,” she says. Give it time and your body will adapt.