Fiber: Key to Insulin Resistance and Lowering Cholesterol

Fiber is a superfood that is key to managing blood sugar, addressing insulin resistance, lowering cholesterol, and supporting healthy gut function. Yet, many people simply don’t get enough of it. According to the 2017-2020 NHANES data, adults 20 years and older eat 16.6 grams daily, far below the recommended levels. 

Recommended Fiber Intake

The recommended dietary fiber intake for the United States of both soluble and insoluble fiber combined is:

  • Females, age 18-50: 25 grams per day
  • Females, ages 51 and above: 21 grams per day
  • Males, ages 18-50: 38 grams per day
  • Males, ages 51 and above: 30 grams per day

In Europe, those recommendations are 25-35 grams per day for adults:

  • Females, 25-32 grams per day
  • Men, 30-35 grams per day

Often underestimated, dietary fiber is a critical contributor to health. According to a 2017 Global Burden of Disease study, 11 million deaths could be attributed to diet. Of these, 1 million were because of low-fiber diets (below 25-35 g/day) and associated disease states like cardiovascular disease and Type 2 Diabetes. Yet in people who consumed at least 25 g/day upwards of 45 g/day of fiber, there was a 15-30% decrease in cardiovascular-related deaths and incidences of other diseases such as Type 2 Diabetes, colorectal cancer, and coronary heart disease (1).

Since health benefits appear dose dependent, I recommend a minimum of 25-29 g/day, if not 30g/day plus, for my clients. 

Types of Fiber

A healthy diet includes different types of fiber. Dietary fiber is a carbohydrate found in a variety of plant foods at differing levels. When we eat fiber, it passes through the body, performing different critical functions along the way. Fiber can be broken down into several types:

Soluble Fiber—This is fiber that dissolves or swells with water and can help with constipation, the digestion of glucose (which helps to lower it), and lowering cholesterol. It is also a beneficial food source for intestinal bacteria.

Insoluble Fiber- This fiber does not dissolve in water and helps move waste through the digestive tract. It remains unchanged and can help increase the weight and volume of bowel movements and help with constipation, hemorrhoids, and diverticulitis.

Resistant starch and inulin are fermentable fiber sources that help feed friendly gut bacteria. 

Key Fiber-Rich Foods

Many of these fiber-rich foods are good for an overall healthy diet and gut health. Eating a high-fiber diet can help mitigate blood sugar spikes and make you feel full longer. If you are unsure where to begin, try writing down the foods in each category that you know you like and then becoming intentional about incorporating them into your dietary intake for one week. Then, the next week, add another food and continue until you’ve incorporated regular intake of each of the following.

When increasing fiber intake, do so gradually. Increasing too much fiber too fast can lead to increased constipation. Also, be mindful of your water intake and aim for about half your body weight in ounces daily to help with soluble fiber absorption and keep things moving through your digestive tract. 

Soluble Fiber

  • Apples
  • Citrus fruits
  • Strawberries
  • Raspberries
  • Psyllium
  • Oats
  • Barley
  • Mushrooms
  • Legumes
  • Chia Seeds

Insoluble Fiber

  • Whole grains
  • Bran
  • Cereal
  • Broccoli
  • Cabbage
  • Legumes
  • Root vegetables
  • Green leafy vegetable
  • Flax

Resistant Starch

  • Underripe bananas
  • Rolled oats
  • White beans
  • Lentils
  • Heated and cooled potatoes
  • Cashews


  • Asparagus
  • Garlic
  • Jerusalem artichokes
  • Leeks
  • Onions
  • Dandelion root
  • Chicory
  • Burdock
  • Bananas

Supplemental Fiber Sources

While whole food sources are key to a healthy diet, sometimes supplementation may be necessary. If supplemental fiber sources are incorporated, these should also be done slowly with adequate hydration to avoid constipation. Dosages vary by manufacturer. 

  • Raw potato starch 
  • Psyllium 
  • Apple Pectin 
  • Inulin Powder 


  1. Pérez-Jiménez, J. (2024). Dietary fiber: Still alive. Food Chemistry, 439, 138076.

Reynolds, A., Mann, J., Cummings, J., Winter, N., Mete, E., & Morenga, L. T. (2019). Carbohydrate quality and human health: A series of systematic reviews and meta-analyses. The Lancet, 393(10170), 434–445.

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