You’ve heard it a million times: Most Americans don’t eat enough fiber. While some reasons go back decades — like our collective preference for pizza over broccoli — some are distinctly modern.

A renewed focus on weight loss, often aided by GLP-1 medications, means some of us now eat less — fiber-rich foods included. At the same time, many Americans are enjoying the protein craze at the expense of plant-based foods.

“Protein is still more famous,” said Katrine Whiteson, PhD, professor of molecular biology and biochemistry at the University of California, Irvine, who studies the human microbiome.

Meanwhile, science keeps pointing to more and more upsides to packing enough fiber into our diet (25-30 g/d for women and 30-38 g/d for men). In a recent commentary published in Nature Food, Andrew Reynolds, PhD, MPH, a research associate professor in medicine at the University of Otago in New Zealand, and his team proposed that fiber should be considered an essential nutrient — like many vitamins the body doesn’t produce on its own.

“It’s so much more than fecal bulking,” he said. “Reduced incidence of cardiovascular disease, type 2 diabetes, colorectal cancer through improved cholesterol, glycemia, blood pressure, and body weight. There are also the lesser-known pathways between gut microbiome and host, with dietary fiber the primary substrate of the gut microbiome, encouraging density, diversity, and functionality.”

The problem isn’t just deficiency: Once you’re reaching the higher ends of the daily recommended amounts — crossing 30 g a day — it’s really easy to eat too much. This is especially true for someone trying to lose weight. Restricting calories while increasing fiber — every single day — can feel like Sisyphus rolling a can of beans instead of a rock.

To help patients get the right amount of fiber, start by explaining why fiber matters and how much they need. Then, share practical ways to hit their fiber targets and support their body composition goals.

Ways to Reframe Fiber in an Everyday Diet

Fiber is like a natural GLP-1 that can help you eat less and lose weight. “Fiber increases satiety and reduces dietary intake through a number of physiological pathways, including those pathways utilized by incretin-based therapies, so adding any fiber to your diet can help with weight-loss goals,” said Reynolds.

Fiber can also reduce the number of calories your body burns. In a 2023 Nature Communications study, researchers monitored study participants in a strictly-supervised metabolic ward, with one group eating a traditional “Western” low-fiber diet and another eating a high-fiber microbiome enhancer diet. Calories remained identical between the groups. The microbiome dieters shed an average of 116 calories/d via feces, giving them the benefits of the better diet while leaving their bodies with fewer calories to process.

Meanwhile, whole grains, legumes, vegetables, fruit, nuts, and seeds tend to be high in fiber and low in calories, which helps displace high-calorie foods from your diet. “We can only eat so much in a day, so by promoting these food groups there is a subsequent reduction in foods that have less fiber,” said Reynolds.

Think of fiber as a macro, like protein. Sarah Khan, MS, RD, LD, a corporate wellness dietitian at Houston Methodist, Houston, sees many patients who prioritize protein to maintain muscle during weight loss — at fiber’s expense. “It’s almost like fiber has become an afterthought, since protein does also induce satiety,” she said. “If they’re being pushed to eat your protein first, then what I’m finding in my practice is that, well, now they’re full and they’re not getting their entire portions of veggies.”

She’s now framing fiber as a new macro to track. Encourage patients to use a food journal app to establish a baseline (25 g/d for women and 38 g/d for men) and track progress toward their target.

Fiber can strengthen your defenses against health threats. Frame eating enough fiber as hygiene for your insides. “The molecular underpinnings of your immune system come from eating fiber and having your microbes turn the molecules in the fiber into really important molecules for sustaining your immune health,” said Whiteson. “It’s really a molecular driver of our immune health, and a lot of people don’t realize that.”

Emerging research even suggests that high-fiber diets might make some cancer treatments work better. “Getting a reasonable amount of fiber is like a basic health thing that you need to do, especially if you are going to have to take antibiotics or chemotherapy drugs,” said Whiteson. She equates the gel that fiber can form to a Brita filter in your gut.

Fiber isn’t just for constipation — it can improve chronic health conditions. If a patient has any cardiovascular or metabolic risk factors, make a case for how fiber can help. Khan finds that the cholesterol-lowering effects of fiber resonate with many people with elevated low-density lipoprotein levels.

If a patient struggles with the 25g-38g per day goal, she starts with a smaller goal: increasing their soluble fiber intake by 5-10 g. She explains that just 5 g 10 g of soluble fiber can form a gel in the intestines, delaying gastric emptying and capturing extra bile acids where cholesterol is packed.

Research concurs. A 2025 Frontiers in Medicine study analyzed prospective data from nearly 11,000 people with metabolic syndrome for 19 years and found lower all-cause and cardiovascular disease mortality risk at a threshold of just 22 g/d. And while mortality risk rose as the fiber amounts dropped, fiber eaters still enjoyed lower overall risk.

You can add fiber even if you have gastrointestinal [GI] symptoms. Carolyn Newberry, MD, a gastroenterologist at New York-Presbyterian and Weill Cornell Medicine, sees many patients, including GLP-1 users, who worry that adding fiber will cause GI symptoms — or worsen existing ones. “Their guts are a little bit slower than they used to be, so they’re nervous about fiber,” she said. “It’s a slow titration upwards and figuring out what fiber is going to be better tolerated.”

She often starts them on foods with less fermentable fibers, such as flax seeds and chia seeds, to minimize gas and bloating. Eventually, as their gut microbiomes adjust, they can ramp up their intake and tolerate more fermentable fibers like the fructans in cruciferous vegetables. Drink more water as you add fiber to reduce the risk for constipation.

You can hit your fiber targets on a budget. Some people assume that if they can’t afford a steady supply of fresh fruits and vegetables, they can’t eat enough fiber. Samantha Snashall, RDN, LD, a staff dietitian focused on weight management at The Ohio State University Wexner Medical Center, helps patients find high-fiber foods that fit their budget. Key players: Frozen fruits and vegetables and canned or dried beans are inexpensive and convenient.

How to Add More Fiber Without Overeating

Newberry talks about fiber with nearly every patient at every visit. “So many medical providers will tell patients they need to eat more fiber but don’t really give practical advice on how to actually do that,” she said.

The central idea: Make fiber a higher percentage of total calories consumed.

Do some quick math. Newberry recommends calculating the carbohydrate-to-fiber ratio on packaged foods before you buy them, especially if you’re trying to lose weight. Divide the total grams of carbs by the grams of fiber. Aim for foods with a ratio of 5:1 or less.

Make sure every meal (and snack) has fiber. If you only eat fiber at breakfast, lunch, and dinner, you really need to pack it in (8-12 g per meal). So follow this rule — every snack must increase your fiber count. Khan finds that people who eat fiber-free snacks often have cravings later in the afternoon or evening, which leads to overeating. Newberry recommends protein-fiber pairings: carrots with a cheese stick, yogurt with berries, or hummus with celery.

Substitute fiber-rich ingredients into the foods you already eat. To increase his fiber intake, Reynolds started simple: replacing white bread and rice with whole-grain brown bread and brown rice. He now prefers their more nutty, complex flavors. Then, he started modifying meat-based recipes. He replaces half the ground beef with brown lentils, black beans, or kidney beans, and half the chicken with cannellini, navy, or butter beans.

Newberry is always adding more fiber to her family’s meals. She makes muffins with ground flax seeds, chia seeds, and whole wheat flour or oat flour. She uses chickpea or lentil pasta instead of regular pasta. Each substitution gets you closer to your target.

Keep berries in your freezer. A cup of frozen raspberries has almost 10 g of fiber and just 86 calories — making it one of the best choices for maximizing fiber, not calories. Bonus: “They’re cheap and delicious and people like them,” said Whiteson. Add them to a smoothie to help fill your fiber gap.

Use seeds like sprinkles. Newberry recommends sprinkling a tablespoon of ground chia seeds on yogurt, oatmeal, or fruit at breakfast or pasta or soup at lunch or dinner. An ounce of chia seeds has nearly 10 g of fiber for 138 calories.

Eat more beans. “About half the carbs in beans and lentils are in the form of fiber,” said Whiteson. She makes beans in a slow cooker to add to salads or soaks dried beans in boiling water overnight, then blends in sautéed onions, chipotle peppers, cumin, and salt. “I’ve definitely had people hear me giving talks through the years who will go on a bean kick and tell me years later that they have been eating a cup of beans every afternoon for years,” she said. Try navy beans — they have 13.4 g of fiber and 296 calories per cup.

Bolster the meals you don’t cook. Many people trying to lose weight opt for preportioned meals from delivery services, which often contain just 3-4 g of fiber, said Khan. That isn’t enough unless you’ve packed a lot of fiber into the rest of the day. Add frozen veggies — a cup of frozen broccoli packs almost 6 g of fiber for just 52 calories.

If you’re at a restaurant with build-your-own salads or bowls, pile yours with nonstarchy, cruciferous vegetables: broccoli, cabbage, cauliflower, or kale, suggests Khan. They’ll pack in more fiber than cucumbers or other more water-based vegetables.

Leverage a vegetarian cookbook. Even if you’re a carnivore, flipping through a vegetarian cookbook can give you new ideas for cooking with fiber-rich plant-based foods. Snashall finds that people tend to enjoy vegetables like broccoli more once they learn a cooking/seasoning method they like, such as roasting to bring out the vegetables’ natural sweetness.

Consider a supplement if you need a boost. A food-first strategy is best since fiber-rich foods contain beneficial vitamins, minerals, and antioxidants. However, all our experts say a psyllium-based fiber supplement can help you cross the finish line when you’re falling short of your target.