How much fiber you eat can strongly influence your overall health. Fiber supports healthy digestion and has been linked to a lower risk of certain cancers, among many other benefits. That growing awareness may help explain why the "fibermaxxing" trend is gaining attention.
Fibermaxxing refers to consuming at least the recommended daily amount of fiber for your body weight each day. The idea has gained traction across social media and traditional media this year.
Jennifer Lee is a scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. Her research focuses on how shifts in gut health and differences between sexes affect metabolism throughout a person's life.
Lee says she is not surprised that fibermaxxing has become popular. In fact, she sees it as a sign that more people are recognizing an important distinction between lifespan and healthspan. Living longer does not necessarily mean living those years in good health, so many people are searching for ways to stay healthier as they age.
"There is a nine-year gap between living to a certain age in good health and then living in poor quality of health at the end of your life," Lee added. "Behavioral or nutritional strategies that can keep someone healthy are very on trend right now."
Research shows that consistently low fiber intake can contribute to metabolic and cardiovascular problems, including diabetes and obesity.
"If you're not consuming a lot of fiber, you're possibly consuming calories from other macronutrient groups, and they may be high in carbohydrates or fats, which can lead to weight gain," Lee said. "Then, depending on a number of factors that may impact one's cancer risk, a fiber deficiency may increase your risk for certain cancers, such as colorectal, breast, and prostate cancer."
Overall, Lee explained that adding more fiber to your daily diet tends to produce wide ranging health benefits.
How Much Fiber Do I Need?
You can find a detailed recommendation for your personal nutritional intake via the USDA's National Agriculture Library Dietary Reference Intakes (DRI) calculator .
Meeting Daily Fiber Intake Recommendations
According to the Dietary Guidelines for Americans, 2020-2025 , published by the United States Department of Agriculture (USDA) and United States Department of Health and Human Services, adults should consume between 22 and 34 grams of fiber each day, depending on age and sex.
Lee also pointed to a simple guideline. For every 1,000 calories consumed, people should aim for about 14 grams of fiber. As people get older and typically eat fewer calories, their recommended fiber intake decreases accordingly.
"For someone between 19 and 30 years old, a female's average recommended daily fiber intake would be 28 grams, based on a 2,000-calorie diet," Lee said. "But for a male in that same age range, the recommended amount of fiber increases to 34 grams because they're eating a little bit more."
Soluble vs. Insoluble Fiber
Lee noted that dietary fiber falls into two main categories. Soluble fiber dissolves in water and slows digestion, while insoluble fiber helps move waste through the digestive tract.
"Soluble fiber attracts water into your gut and forms a gel-like substance," Lee said. "It keeps you full, helps you feel satiated, and once it makes it into the colon, can provide or serve as a substrate for microbiota, meaning your microbiota can metabolize the food that you digest as well. So, this type of fiber serves as a beneficial food source for the microbes."
Soluble fiber can also help regulate blood sugar by slowing digestion and reducing sudden spikes in glucose levels. It may also help lower cholesterol by preventing some cholesterol from being absorbed into the bloodstream.
Foods rich in soluble fiber include many fruits and vegetables, such as apples, avocados, bananas, cabbage, broccoli, and cauliflower. Legumes, beans, and oatmeal are also good sources. Insoluble fiber is commonly found in whole grains, nuts, and seeds.
"Insoluble fiber, on the other hand, cannot be dissolved and will not contribute to the calories you consume," Lee said. "The body can't take up energy from insoluble fiber, but it is critical to consume because it's the bulk of substrate that helps you have a bowel movement. Because insoluble fiber bulks up your stool, it helps to prevent constipation."
To maintain a healthy balance, Lee recommends consuming roughly twice as much insoluble fiber as soluble fiber each day. For example, if your daily goal is 30 grams of fiber, about 20 grams should come from insoluble fiber and 10 grams from soluble fiber.
How Can I Eat More Fiber?
The U.S. Centers for Disease Control and Prevention put together a resource on how fiber can help to manage diabetes, which includes tips for adding more fiber to your diet by eating things like fiber-friendly breakfasts.
Fiber Supplements and Potential Side Effects
For people who struggle to get enough fiber through food alone, supplements may help fill the gap. Lee noted that many adults fall short of recommended fiber intake levels, making supplementation a practical option in some cases.
"The majority of adults are not meeting their dietary fiber intake levels, so generally supplementation is a good strategy to meet recommended levels."
Fiber supplements are available as capsules or powders that can be mixed into drinks. However, Lee cautioned that increasing fiber intake too quickly can cause digestive issues while the body adjusts.
"You could run into the extremes of eating too much, where if you're not drinking enough water to hydrate and exceed the amount of soluble and insoluble fiber, you can get constipated," Lee said. "The other extreme is that some people respond differently to fiber and they run the risk of getting diarrhea. You really should check in with your body, since you know how your body is responding to what you're challenging it with daily."
