Top doctor shares 4 reasons to prioritize fiber for longevity

Dietary fiber is often overlooked, yet top clinicians now consider it one of the most powerful, low-effort tools for long-term health. Far beyond simply aiding digestion, fiber influences core systems that determine how well, and how long, we live. Modern studies consistently link higher fiber intake with reduced cardiovascular risk, improved metabolic markers, stronger gut microbiome function and lower inflammation.
Recently, leading cardiovascular surgeon Dr. Jeremy London highlighted these benefits in an Instagram video, outlining four reasons why prioritizing fiber may significantly support longevity. Dr. London states “if you care about living longer and better, fiber is one of the simplest and most powerful tools that you have.”

Below are four reasons why fiber matters so much for longevity, as per cardiovascular surgeon Dr. Jeremy London.

Dr. London says, the first reason is that fiber provides cardiometabolic protection. He adds, “it (fiber) lowers circulating LDL cholesterol, and combats insulin resistance. The same levers I'm trying to optimize in every patient I operate on”.
Higher fiber intake is consistently associated with lower risk of cardiovascular disease and improved lipid and glucose markers. Meta-analyses of large prospective studies show that people with higher dietary fiber intakes have substantially lower risk of CVD and cardiovascular mortality. As per NIH, soluble fibers (oats, legumes, psyllium, pectin) can bind bile acids and reduce cholesterol reabsorption; fiber also slows carbohydrate absorption and improves insulin sensitivity.

Dr. London says, “fiber increases stool bulk, which keeps things moving. That's not just comfort, that reduces the risks of constipation, diverticular disease, and even colon cancer.
Studies strongly support the ideas of reduced risk of constipation and diverticular disease. Additionally, a 2015 study published in the Journal of Clinical Nutrition found that individuals with higher total dietary fiber intake had a significantly lower risk of developing distal colorectal adenomas, the precancerous growths that often precede colorectal cancer. The researchers concluded that fiber’s ability to increase stool bulk, speed up transit time, and reduce exposure of colon cells to carcinogens may explain its protective effect.

The third reason Dr. London shares that fiber supports microbiome health. “Fermentable fibers feed the gut bacteria, which produce short-chain fatty acids, powerful molecules that reduce inflammation, improve insulin sensitivity, and support your overall immune health”, he adds.
Supporting Dr. Jeremy’s take, studies suggest fermentable fibers increase production of short-chain fatty acids (SCFAs: butyrate, propionate, acetate) by gut bacteria, which in turn help regulate inflammation, maintain gut barrier function, and influence metabolic health including insulin sensitivity.

According to Dr. Jeremy London, fiber increases satiety and slows gastric emptying, and helps prevent over-eating, not through willpower, but by making one feel full.
Observational studies reinforce that higher fiber intake is associated with lower BMI and better long-term weight control. For example, a study published in ScienceDirect found that adults with higher dietary fiber consumption had significantly lower measures of body fat and body weight compared to those consuming less fiber.

“In reality, most adults consume far less than the daily recommended fiber, which is 25 grams for women and 38 grams for men,” notes Dr. Jeremy London. For Dietary fiber intake, Dr. London adds, whole foods like legumes, whole grains, vegetables, fruits, nuts, and seeds are the best sources.

Practical tips to boost fiber intake:
- Swap refined cereals for oatmeal, bran flakes, or whole-grain toast. Top with fruit, chia, or flax seeds.
- Add beans, lentils, or chickpeas to salads, soups, stews, or even as side dishes.
- Choose nuts, seeds, or fresh fruit instead of processed snacks.
- Sprinkle chia, flax, or pumpkin seeds on yogurt, salads, or cereals for extra fiber and healthy fats.
- Drink plenty of water to help fiber move through the digestive system efficiently.