Most Canadians aren’t getting enough fibre—and, therefore, the consequences extend far beyond digestion.
In Canada, adults consume far less fibre than recommended, with men averaging 18.4 grams per day and women 16.2 grams per day. Health Canada recommends 38 grams of fibre per day for men and 25 grams for women.
Research suggests that consuming 25 to 29 grams of fibre per day may help reduce the risk of noncommunicable diseases, while intakes above 30 grams per day may confer additional health benefits.
Despite influencing nearly every major body system, fibre remains one of the most overlooked nutrients in the modern diet. While best known for supporting regularity, research suggests it also plays a vital role in metabolic health, hormone health, healthy aging, and even brain function.
Types of fibre
Soluble fibre dissolves in water, forming a viscous, gel-like substance. Soluble fibre is fermented by gut microbes in the large intestine, a process that produces short-chain fatty acids (SCFAs).
Several compounds make up soluble fibres:
- pectins (apple, cabbage, kidney beans)
- gums (guar gum, acacia gum, xanthan gum, locust bean gum)
- inulin (chicory root, onion, Jerusalem artichoke)
- beta-glucans (oats, barley, mushroom, baker’s yeast)
Insoluble fibre does not dissolve in water and does not form a viscous solution. These fibres are generally less fermentable in the large intestine. Insoluble fibres primarily contribute to stool bulk and intestinal transit.
Several compounds make up insoluble fibre:
- lignin (whole grains, bran, root vegetables, green beans, flaxseeds)
- cellulose (bran, legumes, cabbage, peas)
- certain hemicelluloses (bran, nuts, legumes, whole grains)
Most fibre-rich foods contain a combination of both soluble and insoluble fibre, rather than just one type. On average, fibre-containing foods provide approximately one-third soluble and two-thirds insoluble fibre.
How to close the fibre gap
- Eat vegetables and/or fruit at every meal.
- Eat beans or legumes three times per week.
- Learn new fibre-focused recipes for breakfast, lunch, dinner—and dessert!
- Swap refined grains for whole grains.
- Try pasta alternatives such as chickpea or lentil noodles.
- Munch on nuts as a snack; add them to dishes such as yogurt, oatmeal, and salads.
- Add 1-2 Tbsp of chia or ground flax seeds to smoothies.
- Read nutrition fact labels and aim for foods with 5 or more grams of fibre per serving.
The gut microbiome
Fibre doesn’t simply pass through the digestive tract. Some of it becomes fuel for the gut microbiota, whose metabolites can influence the health of the gut—and the body as a whole.
Microbes in the gut perform many roles, including protecting against pathogens, synthesizing vitamins, metabolizing xenobiotics (such as pharmaceuticals, pesticides, and other environmental chemicals), and contributing to the communication between the gut and brain.
One of their key functions is fermenting the types of dietary fibre that escape digestion in the small intestine. This process produces SCFAs—particularly acetate, propionate, and butyrate.
Short-chain fatty acids
SCFAs are used as energy sources by intestinal cells, influencing the integrity of the intestinal barrier, immune regulation, and metabolic processes.
Their effects may extend well beyond the gut, as SCFAs act as signalling molecules throughout the body. SCFAs can activate signalling pathways in tissues including the liver, lungs, brain, pancreas, bones, and adipose (fat) tissue and may influence the inflammatory processes and pathways involved in cancer development.
Fibre diversity
The amount and types of fibre in the diet help shape the activity of the gut microbiome.
Different fibres provide fuel for different microbial communities, which means that fibre diversity may matter as much as fibre quantity. For example, studies of inulin-type fibres have found increases in certain probiotic groups, including Bifidobacterium and Lactobacillus.
The goal isn’t just to close the fibre gap but also to consume a diverse range of fibres that support a thriving microbiome.
Metabolic health
Satiety
Whole foods that are rich in fibre require chewing and retain much of their physical structure in the gut. The volume-boosting effect of fibre promotes satiety and often results in reduced frequency of food consumption.
Blood sugar and weight management
Fibre impacts glucose and lipid metabolism, promotes insulin sensitivity, and contributes to healthy weight management.
Early research has demonstrated that SCFAs may also directly influence gut motility, suppress appetite, and enhance insulin sensitivity.
Human research has corroborated the beneficial effects of SCFAs on weight management, reduced intra-abdominal adipose tissue volume, reduced fat stored in liver cells, and improved insulin sensitivity.
Randomized clinical trials show significantly lower body weight, systolic blood pressure, and total cholesterol among those with higher intakes of dietary fibre compared to those with lower intakes. Cohort studies report an association between high fibre intake and lower incidence of and mortality from coronary heart disease, along with lower incidence of type 2 diabetes.
A trial conducted among those with type 2 diabetes showed that an intervention providing 15 to 20 grams of soluble viscous fibre daily was associated with beneficial alterations in gut microbiota, along with decreased body mass index, waist circumference, average blood sugar over two to three months, and LDL (bad) cholesterol.
A systematic review showed that a high-fibre diet among those with type 2 diabetes is also associated with reductions in C-reactive protein, a marker of inflammation.
Hormone health
The body is constantly striving for a state of balance called homeostasis. This involves keeping hormone activity within an appropriate physiological range—and closing the fibre gap can help.
Women’s hormone health
Estrogen metabolism: When it comes to estrogen, this involves more than just the help of the ovaries and endocrine tissues—its regulation also involves the liver and gastrointestinal tract.
Once estrogen has circulated through the body, the liver conjugates estrogen to make it water-soluble. Some conjugated estrogens are excreted into bile and delivered to the intestine, where they can be eliminated in stool.
However, certain gut bacteria produce an enzyme called β-glucuronidase, which deconjugates the estrogens, allowing them to be reabsorbed and returned into circulation through a process known as enterohepatic recirculation.
Changes in gut microbial estrogen metabolism may alter estrogen availability, and altered estrogen exposure may be one factor influencing risk in estrogen-sensitive disease, such as endometriosis and breast cancer.
The SCFA butyrate has been shown to strengthen the tight junctions in the intestine, a process that reduces its permeability, potentially limiting excessive estrogen reabsorption. Research suggests that dietary strategies to promote SCFA production and support bile acid signalling may contribute to estrogen homeostasis.
You can support bile acid signalling through daily habits:
- prioritizing a diverse intake of high-fibre foods
- consuming polyphenol-rich foods (berries, cocoa, tea, coffee, herbs, spices, extra-virgin olive oil)
High fibre intake, particularly from fruits, vegetables, and whole grains, may be associated with a reduced risk of endometriosis.
A 2020 meta-analysis found that high total fibre consumption was associated with a reduced risk of breast cancer. This association was also observed for soluble fibre and was consistent among women with both premenopausal and postmenopausal breast cancer.
Men’s hormone health
Higher fibre intake may enhance men’s hormonal health indirectly by supporting healthy body weight and metabolic profile—both important influences on male sex hormones.
Excess adiposity—particularly visceral and central adiposity—is associated with poorer male reproductive hormone profiles. Meanwhile, weight loss in men with obesity is often associated with improvements in testosterone.
Insulin resistance has been shown to suppress the function of the testes, where the bulk of testosterone is produced. This creates a vicious cycle, since low testosterone may further contribute to insulin resistance.
Since fibre has been shown to improve insulin sensitivity and support weight management, focusing on a high-fibre diet may indirectly benefit men’s testosterone levels.
Gut-friendly keywords
- Fibre-rich foods promote regularity. Think plant-based foods in general: veggies, fruit, grains, beans, legumes, nuts, and seeds.
- Probiotics are health-promoting live microorganisms found in fermented foods such as yogurt, kefir, kimchi, and sauerkraut.
- Prebiotics are a subset of dietary fibres that are metabolized by beneficial microorganisms to promote overall health; they are found in garlic, onions, leeks, asparagus, Jerusalem artichokes, and green bananas.
Chronic disease and healthy aging
Research shows that fibre intake may play a vital role in the prevention and management of chronic disease while also promoting longevity.
In a large series of systematic reviews and meta-analyses, those with the highest dietary fibre intake had an estimated 15 to 30 percent lower risk of all-cause mortality and incidence of coronary heart disease, stroke, type 2 diabetes, and colorectal cancer compared to those with the lowest fibre intake.
One meta-analysis showed that each 10-gram per day increase in daily fibre consumption was associated with an 11 percent reduction in all-cause mortality. Cereal fibres in particular (such as oat, bran, hulled barley, and cornmeal) were associated with the strongest inverse association with mortality.
This effect might, in part, derive from fibre’s impact on the gut microbiome and inflammation.
Limited dietary fibre prevents the establishment of a diverse microbiome, which in turn reduces the production of SCFAs. Alterations in the gut microbiome have been implicated in chronic conditions including obesity, diabetes, cancers, and cardiovascular disease.
Low dietary fibre intake is also a risk factor for both local and systemic inflammation. A 2020 study showed that those with the highest dietary fibre intake had significantly lower markers of inflammation in the blood compared to those with the lowest intake.
Chronic low-grade inflammation is associated with the development of chronic conditions including obesity, cardiovascular disease, and cancer, along with overall mortality.
Brain health
Gut-brain axis
A healthy and diverse gut microbiome underlies normal physiology, including mental and emotional functioning. The gut communicates with the brain via the gut-brain axis through several mediators, including SCFAs.
SCFAs assist in maintaining the integrity of the blood-brain barrier, regulate microglial activity in the central nervous system, modulate inflammatory pathways, and affect gene expression through epigenetic mechanisms.
Cognition
Dietary fibre has been associated with beneficial effects on mood and cognitive processes, including attention, mental flexibility, and executive functioning.
A 2026 prospective Japanese study showed that dietary intake of total, soluble, and insoluble fibre was associated with a lower risk of disabling dementia in both men and women.
In adults aged 60 and above, a high fibre intake has been associated with better processing speed and memory.
A 2024 placebo-controlled trial among adults aged 60 years and above showed that a daily prebiotic fibre intervention was associated with improved visual memory and new learning compared to placebo.
Depression
A high fibre intake is also associated with a reduced risk of depression. It’s theorized that the reduction in inflammatory compounds associated with a high-fibre diet may alter the concentration of neurotransmitters that promote the development of depression.
Fibre may also be beneficial as a dietary support in the management of depression, anxiety, and chronic stress.
Closing the fibre gap
Closing the fibre gap isn’t the latest nutrition trend—it’s about returning to one of nature’s most powerful foundations of health. By noshing on a diversity of fibre-rich foods each day, you’re not only supporting your digestion but also nourishing your microbiome and supporting hormone balance, a sharper brain, and healthier aging for years to come.
What happens after you eat?
From the dining room to the bathroom—and far beyond!
| DIGEST | 0-30 minutes | Digestion begins in the mouth and stomach. Food is mechanically broken down by chewing and chemically broken down by stomach acid and digestive enzymes.
Fibre influences satiety, gastric emptying, and the absorption of nutrients. |
| 30 minutes-2 hours | Nutrients enter the small intestine for absorption. Digestible carbohydrates are broken down into simple sugars, including glucose, which are absorbed into the bloodstream and used for energy. | |
| METABOLIZE | 1-3 hours | The pancreas responds by secreting insulin. Insulin promotes glucose uptake and storage, helping move blood glucose levels to pre-meal levels.
Meal composition and fibre types can alter the post-meal glucose response and the release of satiety hormones. |
| FERMENT | 3-24+ hours | Undigested fibre reaches the large intestine.
Gut microbes ferment certain types of fibre to produce short chain fatty acids (SCFAs), including acetate, propionate, and butyrate. Different fibre types influence the growth and diversity of microbial species. |
| SIGNAL | hours to days | SCFAS acids interact with the gut and influence metabolic, immune, inflammatory, and brain-signalling pathways. |
| MOVE | days | Fibre may increase stool bulk, influence stool water content, and affect intestinal transit. |
| ADAPT | weeks to months | The effects of fibre, including stool regularity and the production of microbial metabolites, may influence the gut-brain axis and support gastrointestinal, cardiometabolic, and immune health. |
Fibre IQ
| Food | Fibre per serving |
| black beans | 10.5 g per 3/4 cup (180 mL) |
| yellow beans | 9.7 g per 1/2 cup (125 mL) |
| all bran cereal | 9.7 g per 1/2 cup (125 mL) |
| chia seeds | 7.4 g per 2 Tbsp (30 mL) |
| avocado | 6.7 g per 1/2 fruit |
| edamame | 6 g per 3/4 cup (180 mL) |
| lentils, cooked | 5.5 g per 3/4 cup (180 mL) |
| raspberries | 4.1 g per 1/2 cup (125 mL) |
| apple, with skin | 3.5 g per 1 medium |
| quinoa, cooked | 2.7 g per 1/2 cup (125 mL) |
| oatmeal | 3.2 g per 3/4 cup (180 mL) |
| flaxseed, whole | 2.9 g per Tbsp (15 mL) |
| peanut butter, natural | 2.5 g per 2 Tbsp (30 mL) |
| brown rice, cooked | 2 g per 1/2 cup (125 mL) |
| white bread | 0.8 g per slice |
| white rice, cooked | 0.4 g per 1/2 cup (125 mL) |
| meat and eggs | 0 g |
This article originally appeared as ‘Closing the fibre gap’ in the November 2026 issue of alive.