Protein may be all the rage right now, but there’s something else you may be neglecting in your diet: fiber. Undeniably less sexy, fiber is one of the most critical nutritional facets of a healthy diet. Unfortunately, it’s often overlooked, with statistics reporting that 95% of people are deficient in it. So, what to do? And how do you know if you’re eating enough, almost enough, or entirely not enough at all?

Why is fiber so important?

Fiber is a type of indigestible carbohydrate found in fruit, vegetables, beans, nuts, seeds, and grains. Because it’s indigestible, fiber helps to bulk up stool and helps it move throughout the digestive tract at a steady rate.

Nutritionist Rose Ferguson is quick to note, though, that fiber’s role goes way beyond just good digestion. “Yes, it keeps things moving, but fiber also feeds the gut microbiome, helps regulate blood sugar, lowers inflammation, and supports detoxification pathways through the liver and bowels,” she explains to Vogue. “It’s foundational.”

What are the two types of fiber?

Fiber comes in two forms: soluble and insoluble. Soluble fiber dissolves on contact with water to create a gel-like liquid that can help slow digestion and maintain balanced blood sugar. Insoluble fiber, on the other hand, does not dissolve and is found in fruits, vegetables, nuts, seeds, beans, and grains. This is the type of fiber that helps to bulk up food and efficiently move it through the digestive tract.

How much fiber should you eat per day?

In the UK, the NHS recommends that adults eat 30 grams of fiber per day. (For reference, a medium apple contains 3 to 4g, a 40g bowl of bran flakes has about 7 g, and a can of chickpeas has 16 to 17g.) For Ferguson, though, there’s a higher gold standard to hit when it comes to fiber. “In functional medicine, we often go a step further, aiming for 35 to 50 grams daily, especially when we’re supporting things like gut health, hormonal balance, or blood glucose. That might sound like a lot, but it’s entirely achievable when you focus on increasing plants in your day-to-day: think veggies, legumes, seeds, and diverse grains.”

7 signs you’re not eating enough protein

Chances are, unless you’re making a concerted effort, you’re not eating enough fiber. Hitting 30g, let alone Ferguson’s recommendation for 35 grams plus, is doable, but it requires attention and consistency. Outside of tracking your food, though, there are some physical signs that you might not be eating enough fiber.