What You're Really Missing in Your Diet: The Fiber Gap

Updated July 2026

As a cardiologist deeply invested in preventive health, I've observed a common trend: while many people are preoccupied with protein intake, a significant number are neglecting a vital nutrient — fiber. Despite its essential role in maintaining overall health, fiber doesn't receive nearly the attention it deserves.

How much fiber are most people actually getting?

Far too little. According to a comprehensive study on fiber intake, less than 5% of Americans meet the recommended daily intake for dietary fiber. That's a 95% deficiency rate for a nutrient proven time and time again to reduce the risk of chronic disease. The statistics are almost exactly flipped for protein: more than 92% of women consume enough protein to meet their estimated average requirements, an 8% deficiency rate. Many of us consume more than double the protein we need.

The minimum recommended daily intake for fiber is 25 grams for women and 38 grams for men, but the average adult only gets about 15 to 16 grams per day. That shortfall, often called the “fiber gap,” has significant health implications. If you want the practical version of how to close it, see how much fiber you really need.

Why does fiber matter more than most people think?

Fiber is not just about keeping you regular. It's a key regulator of metabolism, inflammation, appetite, and immune function, and it drives better cardiometabolic outcomes, including lower all-cause mortality, reduced risk of cardiovascular disease, improved lipid profiles with lower total and LDL cholesterol, better blood pressure regulation, reduced incidence of type 2 diabetes, and lower body weight. All from getting more fiber. And if that's not enough, higher fiber intake also comes with decreased risk of colorectal and breast cancer.

How does fiber connect to GLP-1 and appetite?

Through your gut bacteria. One of the most fascinating insights from current research is fiber's impact on GLP-1 (glucagon-like peptide-1), a hormone that helps regulate insulin secretion, blood sugar, and satiety.

When you eat fiber, particularly the soluble and fermentable types found in foods like oats, flaxseeds, legumes, and berries, it feeds your gut bacteria. In return, these microbes produce short-chain fatty acids that trigger the release of GLP-1. This hormonal cascade slows digestion, curbs appetite, and helps prevent overeating. It's why so many Step One customers report feeling fuller longer and having fewer cravings. That's whole-food fiber at work, activating a powerful metabolic feedback loop.

If “GLP-1” sounds familiar, it's because this is the hormone delivered by drugs like Ozempic, Wegovy, Mounjaro and Zepbound. And in case you're wondering why we're injecting pharmaceutical GLP-1 into people in the setting of near-universal fiber deficiency, instead of first making sure that fiber gap is closed so GLP-1 levels can rise naturally, welcome to my indignation.

What happens when fiber intake stays low?

Low fiber intake is a public health crisis. It's directly linked to obesity and weight gain, elevated cholesterol, hypertension, insulin resistance, and inflammation. Is it any wonder our society is awash in heart disease, prediabetes, diabetes, obesity, and chronic pain, and that we're seeing more colorectal cancer in younger and younger people? While medications can address some of these issues, fiber works upstream, helping prevent these problems from occurring in the first place.

Not all fiber is equal, though. To understand why the fiber added to processed foods doesn't do the same work, see the dangers of the wrong fiber and whether fiber supplements measure up to fiber from food. And because your body needs a range of fiber types, not just a big number, it's worth understanding why fiber variety matters. If adding fiber has ever left you bloated, here's how to add it without digestive trouble.

How can you close the fiber gap?

This is exactly why I created Step One Foods. Two daily servings of our products deliver at least 10 grams of fiber, using only whole-food ingredients like chia seeds, oats, and walnuts. These foods naturally provide the types of fiber — soluble, insoluble, and fermentable — that your body and microbiome need to function optimally. If the average person is missing about 10 grams of fiber per day, two servings get you there, closing the fiber gap without supplements or drastic diet changes.

Our foods are also backed by clinical data. In a randomized controlled trial conducted with Mayo Clinic and the University of Manitoba, participants who ate Step One Foods twice daily saw rapid, significant reductions in LDL cholesterol.

We've spent decades worrying about fat, carbs, and most recently protein. But if I could get every patient to focus on one nutrient starting today, it would be fiber. The science is clear, the benefits are vast, and the solution is simple: eat more real, whole, plant-based foods. And let Step One help. Your body will thank you. So will your heart.

If you're new to this site and found this useful, I write one of these evidence-based articles every week. You can get them in your inbox by joining my email list at the bottom of this page. No spam, no requirement to buy anything, just practical knowledge.