The Essential Nutrient Missing From Keto Diets

Dietitian Abby Langer explains why we all need to be eating more fibre

With protein-heavy keto-mania in high gear, fibre is swiftly on its way to becoming a forgotten nutrient. That’s a problem, because it’s essential for keeping us regular and helping us feel fuller, longer—and so much more. A 2012 review of studies in the journal Metabolism linked fibre with lower blood sugar and cholesterol, reduced inflammation and a decreased risk of conditions such as diabetes, heart attack and stroke. Fibre is also fuel for our microbiome, a.k.a. the 100 trillion bugs in our guts that are thought to affect everything from our immunity to our weight to our mental health.

How do I get more fibre in my diet?

Fibre—both soluble and insoluble—is typically found in fruits, vegetables, nuts, seeds and whole grains. All fibre travels through the stomach to the large intestine. There, the soluble stuff is fermented by gut bacteria, creating short-chain fatty acids (a.k.a. fuel for your microbiome), while insoluble fibre is either also fermented or passed. And a third type, functional fibres, are non-digestible carbohydrates that naturally occur in plants and are frequently added to foods by manufacturers (look for names like inulin, beta-glucans and cellulose on ingredient lists). These fibres may help with constipation and blood sugar levels; most are also fermentable. A healthy diet has a mix of all three.

The thing is, we’re not eating nearly enough of any type of fibre. The average North American consumes 15 to 18 grams per day due to our highly processed diet. Compare that to the Hadza, a hunter-gatherer tribe in Tanzania that eats entirely unprocessed foods. This may account for the diversity of the tribe’s microbiome (a good thing), which is far greater than those of cultures consuming a westernized diet.

By eating mostly tubers, berries, honey and game meat, the Hadza get 100 to 150 grams of fibre a day. No worries though: Our modern-day daily recommendation is only 21 to 38 grams.

Whatever your diet, get your daily fibre intake from foods like berries and stone fruits, popcorn, brussels sprouts, kale and pumpkin seeds.

Posted May 2019, updated May 2020