We created this fiber guide because fiber plays a critical role in improving insulin resistance, supporting gut health, lowering post-meal blood sugar spikes, and increasing satiety.
And, fiber has other benefits. Getting enough fiber regularly can decrease blood pressure, cholesterol, and even reduce your risk for certain cancers. And, because it increases the GLP1 hormone that helps with satiety, getting enough fiber plays a role in weight management.
Let’s break down where fiber comes from, the two types of fiber, why fiber matters for insulin resistance, how much fiber is recommended each day, and which high fiber foods deserve a regular spot on your plate. If you haven't already, be sure to grab your copy of the Fiber Guide for Insulin Resistance.
What Is Fiber and Where Does It Come From?
Dietary fiber is the indigestible part of plant foods. While fiber comes from foods that have some carbohydrates, most of the fiber doesn't break down into blood sugar (glucose). Fiber mostly passes through the digestive tract intact.
Fiber is only found in plants, including:
- Fruits
- Vegetables (starchy vegetables and non-starchy vegetables)
- Beans and Peas (also called legumes)
- Whole grains
- Nuts and seeds
The Fiber Guide lists how much fiber is in different plant-based foods.
Animal foods (meat, poultry, fish, eggs, dairy) contain zero fiber.
There Are Two Main Types of Fiber: Soluble and Insoluble Fiber
1. Soluble Fiber
Soluble fiber is a type of dietary fiber found in plant-based foods. It's called "soluble" because it dissolves in water, forming a gel-like substance in your digestive tract. This gel helps slow down the digestion and absorption of nutrients, providing various health benefits.
Soluble Fiber Benefits:
- Blood Sugar Control: Soluble fiber slows the digestion and absorption of carbohydrates, helping to stabilize blood sugar levels. This is especially important for people with diabetes.
- Weight Management: Foods rich in soluble fiber can help you feel full longer, reducing overall calorie intake and aiding in weight management.
- Gut Health: Soluble fiber serves as a prebiotic, nourishing beneficial gut bacteria. This can improve gut health, digestion, and overall immune function.
- Heart Health: Soluble fiber can lower cholesterol levels by binding to cholesterol particles and removing them from the body. This can reduce the risk of heart disease.
2. Insoluble Fiber
Insoluble fiber is a type of fiber that doesn't dissolve in water. Instead, it passes through our digestive system mostly intact, acting like a broom. This can have many benefits for our health.
Insoluble Fiber Benefits
- Gut Health: Insoluble fiber adds bulk to your stool and helps food move through your digestive tract. This can prevent constipation and promote regular bowel movements. Beneficial gut bacteria feed on insoluble fiber, which helps keep the gut healthy.
- Weight Management: Foods high in insoluble fiber are often lower in calories and can help you feel full for longer. This can be helpful if you're trying to manage your weight.
- Heart Health: Insoluble fiber may help lower your risk of heart disease by reducing levels of harmful cholesterol in your blood.
- Blood Sugar Control: Including insoluble fiber in your diet helps slow down post-meal blood sugar spikes. This also helps keep insulin levels lower, which works to improve insulin resistance.
Most whole plant foods contain a mix of insoluble and soluble fiber. Because of this reason, the Fiber Guide doesn't differentiate between insoluble and soluble fiber. Instead, the Fiber Guide lists the total fiber amount of different foods.
Why Fiber Helps Insulin Resistance
When someone has insulin resistance, the body’s cells don’t accept insulin as well as they used to (you can read more about this here). This means that the cells are less sensitive to insulin, so the pancreas, the organ that makes insulin, compensates by producing more insulin. Over time, this makes insulin resistance worse.
Higher fiber intake is consistently associated with lower fasting insulin levels and improved metabolic health.
How Much Fiber Do You Need
To calculate your fiber needs, use this simple rule: for every 1000 calories you consume, have ~14 grams of fiber.
So if you eat:
1,600 calories, have at least 22 g fiber
2,000 calories, have at least 28 g fiber
2,500 calories, have at least 35 g fiber
Recommendations around adequate intakes of dietary fiber differ around the world and by age group, but 25-30 g or more daily is widely recommended for adults. You can read more about fiber recommendations in this article.
High Fiber Foods for Insulin Resistance
We list some high-fiber foods here, but the Fiber Guide is a more complete list of fiber amounts in fruits, vegetables, legumes, whole grains, and nuts and seeds.
High Fiber Fruits
| Food | Serving | Fiber (approx) |
|---|---|---|
| Raspberries | 1 cup | 8 g |
| Blackberries | 1 cup | 7–8 g |
| Pear (with skin) | 1 medium | 5–6 g |
| Apple (with skin) | 1 medium | 4–5 g |
| Avocado | ½ medium | 5 g |
Berries are especially helpful for insulin resistance because they provide fiber with relatively lower sugar content compared to tropical fruits.
High Fiber Vegetables
| Food | Serving | Fiber (approx) |
|---|---|---|
| Broccoli | 1 cup cooked | 5 g |
| Brussels sprouts | 1 cup cooked | 6 g |
| Artichoke | 1 medium | 7 g |
| Carrots | 1 cup raw | 3–4 g |
| Spinach | 1 cup cooked | 4 g |
Non-starchy vegetables are especially helpful because they’re high in fiber with minimal impact on blood sugar (glucose).
High Fiber Beans & Peas (Legumes)
| Food | Serving | Fiber (approx) |
|---|---|---|
| Lentils | ½ cup cooked | 7–8 g |
| Black beans | ½ cup cooked | 7–8 g |
| Chickpeas | ½ cup cooked | 6–7 g |
| White beans | ½ cup cooked | 6 g |
| Edamame | ½ cup | 4 g |
Legumes are one of the most powerful foods for improving insulin resistance due to their combination of fiber, protein, and resistant starch.
High Fiber Whole Grains
| Food | Serving | Fiber (approx) |
|---|---|---|
| Oats (rolled) | ½ cup dry | 4 g |
| Barley | ½ cup cooked | 3 g |
| Quinoa | ½ cup cooked | 2–3 g |
| Brown rice | ½ cup cooked | 2 g |
| Farro | ½ cup cooked | 3–4 g |
Whole grains contain fiber in the bran layer, which is removed in refined grains. Be careful, though – whole grains are higher in carbs and should be balanced with protein. You can read about how to balance carbs with protein in our article on Protein To Carb Ratio For Insulin Resistance.
High Fiber Nuts & Seeds
| Food | Serving | Fiber (approx) |
|---|---|---|
| Chia seeds | 1 Tbsp | 5 g |
| Ground flaxseed | 1 Tbsp | 2 g |
| Almonds | 1 oz (23 nuts) | 3–4 g |
| Pumpkin seeds | 1 oz | 2 g |
| Sunflower seeds | 1 oz | 2–3 g |
Seeds are small but mighty — adding 1–2 tablespoons to yogurt, salads, or smoothies can meaningfully increase daily fiber intake.
Printable Fiber Guide
Be sure to get your copy of our printable Fiber Guide.
How to Increase Fiber Without Digestive Discomfort
Most people are getting only 10-15 grams of fiber per day. If you feel your fiber intake is low, it's a good idea to increase your fiber intake gradually. This helps avoid bloating and discomfort.
- Add fiber slowly. You might consider adding 5 grams of fiber per day, per week.
- Increasing water intake is required. Fiber acts as a sponge, absorbing water. Be sure to increase your water intake as you increase fiber.
- Spread fiber throughout the day. If our goal is 25 grams per day, shoot for 7-9 grams per meal (if you are eating 3 meals per day).
This approach supports gut adaptation and minimizes bloating.
Tips for Increasing Fiber Intake
There are several ways to increase your fiber intake, and the image below shares a few. Hopefully, this article helps you choose more whole foods with higher amounts of fiber.
Adding a Fiber Supplement
While this fiber guide focuses on getting fiber from whole foods, there are situations where a fiber supplement can be useful. Whole foods should still provide the majority of your daily fiber because they also contain vitamins, minerals, antioxidants, and plant compounds that support metabolic health and help improve insulin resistance.
However, fiber supplements can still play a supportive role in certain situations.
When a Fiber Supplement May Help
A fiber supplement may be helpful if:
- You struggle to reach 25–35 grams of fiber per day.
- Digestive issues make it difficult to tolerate large amounts of high-fiber foods.
- You are traveling or have limited access to fiber-rich foods.
- Your healthcare provider recommends additional fiber for cholesterol, blood sugar control, or bowel regularity.
Fiber Supplements We Recommend
We often recommend a fiber called Sunfiber (affiliate link). Sunfiber is partially hydrolyzed guar gum (PHGG) and is gentle on digestion and often used for gut health and IBS (irritable bowel syndrome). It dissolves easily and doesn't have much of a taste. You can also get Sunfiber through Fullscript, where we pass on a 30% discount to you (also an affiliate link but you do need to set up an account and then search for sunfiber).
Another fiber supplement that we recommend is a fiber gummy from Organic India (through Fullscript). The fiber in this gummy is from organic Jerusalem artichoke inulin. The gummies don't have any added sugar, taste well and are convenient for travel or when out for dinner.
TIP: Take your fiber supplement with a full glass of water, ten minutes before your largest meal. This can help slow blood sugar (glucose) absorption.
Most of Our Recipes Are Moderate to High Fiber
We know that fiber is foundational to improving insulin resistance and metabolic health. Therefore, we use whole food ingredients in our recipes that are higher in fiber. Here are just a few:
More high-fiber recipes are available on our Recipes page.
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