Coach’s Corner

The Fiber Fix

Using Fiber to Enhance Weight Loss, Heart Health, Blood Sugar Management, and Brain Function with Real Food

Jeni O'Neill

February 21, 2024

Different fruits and vegetables that are rich in fiber

    Forget the tasteless, cardboard cereals of yesteryear.

    Fiber is finally getting the attention it deserves thanks to what we’ve learned about metabolism, lipid management, the gut microbiome, and even brain health.

    When you think about fiber, you may think of high-fiber cereals like the one in a dated Saturday Night Live skit indelicately named for its digestive benefits. I have memories of my grandparents eating bland, shredded wheat bricks. While cereals and supplements do contain fiber, we’ve learned so much since then about how fiber benefits our health.

    Thankfully there are tastier and better ways to make sure we’re getting enough fiber!

    Fiber has been an overlooked nutrient in our modern, macro-centric view of nutrition, which elevates protein, fats, and carbs above all else. Perhaps fiber deserves some more of the spotlight.

    So in this post, I’ll share some reasons that you might want to make fiber a priority in your diet. And I’ll provide some very easy real-food strategies you can start using today.

    Different fruits and vegetables

    First, let’s start with understanding what fiber is exactly.

    What is Fiber?

    • Fiber comes from plants.
      It is composed mostly of plant cell walls. There is no fiber in animal products or oils. Sources of fiber include whole fruits, vegetables, legumes, nuts, and seeds.
    • Fiber is technically a carbohydrate that your body can’t digest.
      While other carbohydrates are broken down into glucose, your body can’t break down fiber, so it passes through the stomach virtually untouched.
    • Soluble fiber, like that found in oats, beans, peas, apples, and carrots, dissolves in water and helps lower blood sugar and cholesterol levels. This type of fiber has more metabolic activity and also serves as more of a prebiotic – feeding your gut microbiome.
    • Insoluble fiber doesn’t dissolve in water but aids in regular bowel movements and prevents constipation. Good sources of insoluble fiber include broccoli (and other cruciferous veggies), quinoa, kale, cauliflower, potatoes, and green beans.

    Why Add More Fiber?

    If you’re a patient at RIFM, your doctor has likely talked to you about adding more fiber to your diet. Why is fiber such a common recommendation?

    Two red apples on a tree

    1. Fiber can help reduce LDL cholesterol and improve cardiovascular health.

      Especially soluble fiber, like that found in apples, carrots, beans, and oats, can help lower cholesterol and improve lipid profiles. Dr. Hartman has talked at length about heart disease, the number one killer of both men and women in the U.S. It’s encouraging to know that simply eating more fiber-rich foods can improve your heart health!

    2. Fiber improves digestive health.

      Fiber can play a dual role in regulating digestive issues. While it can ease constipation by bulking up the stool and allowing it to pass more easily, it can also firm up loose or watery stools. Proper digestion is vital for our overall health and it also makes a big difference in how we feel each day. Having regular bowel movements is critical for detoxification, and can even help regulate our hormones.

    3. Fiber feeds your gut microbiome.

      Prebiotics are simply a type of fiber that feeds our good gut bacteria; these are found in plant foods! Think starchy root vegetables, cabbage, asparagus, almonds, and more. Our gut microbes use these fibers for energy.

    4. Research has shown that increasing fiber intake can aid in weight loss.

      Since fiber soaks up water in the intestine, it slows down the absorption of nutrients and increases feelings of fullness. Food at the end of the small intestine dials down appetite.

      Most processed foods are already absorbed before reaching the end of our small intestine, so they are much less satiating.Gut image

      Fiber also helps to regulate insulin release, which signals our body to let us know if we are still hungry or not.

    5. Fiber allows your body to make postbiotics.

      We talked about prebiotics above. And you’ve heard of probiotics – those good gut bugs that we’re all trying to get more of. But have you heard of postbiotics?

      We’re learning that happy gut microbes transform prebiotic fiber into a lot of other things like short-chain fatty acids, which are very important for overall health.

      These short-chain fatty acids like butyrate, acetate, and propionate help heal our gut lining, strengthening the tight junctions in our gut barrier.

      They also are absorbed into the bloodstream and can cross the blood-brain barrier, improving brain health. Did you know that fiber also promotes the production of brain-derived neurotrophic factor (BDNF), made in the gut? BDNF is like your body’s own brain superfood and is necessary for our brain to heal, repair, and maintain healthy cognitive function. We all want more BDNF!

    6.  Fiber helps our bodies regulate blood sugar.

      Fiber controls blood sugar levels by slowing down sugar absorption in the body and may even reduce the risk of type 2 diabetes

      This effect further regulates insulin release, which helps us to avoid those unpleasant blood sugar roller coaster rides.

    How Much Fiber Should I Eat?


    The average American eats about 15 grams of fiber per day, which is woefully inadequate.

    For optimal production of short-chain fatty acids, we need 40-60 grams of fiber per day. In general, it’s best to get your fiber from organic fruits, vegetables, nuts, and seeds – not processed grains.

    Dr. Hartman often recommends that his patients add 10-20 grams per day in the form of flax and/or chia seeds. Two tablespoons of chia seeds plus two tablespoons of flax seeds per day packs a powerful dose of about 16 grams of added fiber! You can grind them in a coffee grinder or toss them into your smoothie.

    Check out this post about flax seeds for more ways to incorporate flax seeds into your diet.

    40 grams of Fiber: A Sample Day

    Goal in a day is to eat 40 grams of fiber

    How might you get 40 grams of fiber in one day? Eat a lot of plants! There are many, many reasons to eat a plant-forward diet, fiber being only one.

    Note that in this sample day, you would need to add clean protein and healthy fats at each meal as well. This sample day only includes the fiber-rich foods for the day.

    19g of fiber in a breakfast smoothie

    Breakfast Smoothie (19 grams of fiber):
    ½ c (2oz) Blueberries – 2g
    1c (1 oz) Spinach – 1g
    2T Flax Seeds – 6g
    2T Chia Seeds – 10g

    Lunch Salad (8.5 grams of fiber):
    3 c (4.5 oz) Mixed Greens – 2g
    10 slices (2 oz) Sliced Peppers – 1g
    10 slices (3 oz) Cucumber – 1g
    Apple – 4.5g

    Slices of carrots

    Snack (5 grams of fiber):
    12 (3 oz) Baby Carrots – 2g
    2T Hummus – 3g


    Dinner Meat & Veggies (9 grams of fiber):
    1 ¼ cups (6 oz) Broccoli – 5.5g
    1 4-inch (4 oz) Sweet Potato 3.5g

    Total = 41.5 grams of fiber

    The key to getting enough fiber is to make sure you’re eating enough plants! 

    Pro Tips

    1. Using a simple digital scale, weigh your veggies for a few days to see how much fiber you’re getting. You’ll be surprised at how much 6 oz of broccoli is. Digital kitchen scales are fairly inexpensive ($10-$30) and can be easily found at Walmart or on Amazon
    2. Build up slowly when adding lots of fiber into your diet all at once!  We may not have the microbes/enzymes built up to process them all, which can result in gas and bloating. Start where you are and build up from there.

    The Underrated Nutrient

    The significance of fiber in our diets cannot be overstated. From weight management to heart health, blood sugar control, and cognitive function, fiber plays a crucial role in various aspects of our well-being. By adding lots of delicious, fiber-rich foods into our day, we can support our overall health with real food. So let’s embrace the power of fiber and make it a staple in our everyday eating habits for a healthier lifestyle.

    Take up the challenge! Can you eat 40 grams of fiber in one day? We want to know how you did it! Leave us a comment on Instagram or Facebook to let us know. 

    We’ve Updated Our Popular Food Sourcing Guide

    • Food Sourcing Principles
    • Local Sourcing Options for Central VA
    • Non-Local Sourcing Solutions & Principles

    And we’ve added it to our FREE micro course “Real Food Diaries.” Register for the free course to access the updated guide.