Now that I have an actual office again (at least one bigger than a phone booth), I’ve been working on research for my next book, which is about increasing health span. Health span is the length of time in your lifespan during which you are healthy, free of disease, and functional.
Part of the plan for this book is to review the studies and use the data to show my audience the easy things to tackle first that will make the most significant, fastest difference in increasing their health span. So, let’s talk about everyone’s favorite topic: Fiber!
A new study, and it’s one of many on the subject, shows that eating more fiber is inversely associated with all-cause mortality. As in, if you eat more fiber, you will have a higher chance of not getting, or if you do get, surviving, the things that tend to lead to our mortality.
Especially if you’re not getting much — the study shows that the sweet spot for benefit is 21.7 grams a day. If you’re getting under that amount, for every five grams added, you get a reduction of risk from all-cause mortality of 7%. For reference, a large apple has about five grams of fiber.
This study, a Meta-analysis (a study of studies), shows up to a 30% reduction in all-cause mortality with increased fiber consumption.
Look, I know fiber isn’t the most exciting topic in the world, but the benefits are too good to ignore, so I’ll make a list of bullet points for you to skim below:
Better Digestive Health
Soluble fiber feeds beneficial gut bacteria (prebiotic effect), promoting a healthier gut microbiome linked to stronger immunity and reduced inflammation.
Lower Cholesterol Levels
Soluble fiber (oats, beans, apples, etc.) binds to cholesterol in the digestive system and helps remove it from the body, reducing LDL (“bad”) cholesterol and total cholesterol. The cholesterol benefits are why I started adding psyllium husk to my “poor man’s Ozempic.”
Improved Blood Sugar Control
Fiber slows the absorption of sugar, reducing blood-sugar spikes after meals. This is especially beneficial for people with prediabetes, type 2 diabetes, or insulin resistance.
Weight Management & Increased Satiety
High-fiber foods tend to be more filling, so you feel full longer and naturally eat fewer calories. Studies show people on higher-fiber diets tend to have lower body weight and less weight gain over time.
Reduced Risk of Cardiovascular Disease
Through lower cholesterol, better blood pressure, reduced inflammation, and improved blood sugar, higher fiber intake is consistently linked to lower risk of heart disease and stroke.
Lower Risk of Colorectal Cancer
An increase in dietary fiber is associated with roughly a 7–10% lower risk of colorectal cancer, likely due to faster transit time and dilution of carcinogens.
Reduced Risk of Diverticular Disease
Long-term high fiber intake (especially from fruits, vegetables, and whole grains) dramatically lowers the risk of developing diverticulosis and diverticulitis. If you’ve ever had or known someone to have a bout of diverticulitis, you know for sure you don’t want that.
Lower All-Cause Mortality
Meta-analyses of prospective studies (e.g., 2019 review in The Lancet) found that people with the highest fiber intake have a 15–30% lower risk of dying prematurely from any cause compared to those with the lowest intake. Not dying is pretty awesome.
Better Skin Health (indirect)
Through improved gut health and reduced systemic inflammation, some people notice clearer skin and fewer breakouts.
So, do yourself a favor and get a little more fiber in your diet. It’s easy to do, and the benefits are too good to ignore. And I’d like to point out that I wrote this entire article without making any bathroom jokes! I must be maturing. Finally.
Until next time,
Doc G
