Why fiber is so important and how to eat enough of it
What is fiber? Fiber is a complex carbohydrate found only in plant foods that your body cannot break down. The carbohydrates you get from foods like bread, grains, or potatoes get broken down and converted into sugar and used for energy. Conversely, our bodies don’t have the enzymes needed to bread down fiber, so it […]
What is fiber?
Fiber is a complex carbohydrate found only in plant foods that your body cannot break down. The carbohydrates you get from foods like bread, grains, or potatoes get broken down and converted into sugar and used for energy. Conversely, our bodies don’t have the enzymes needed to bread down fiber, so it moves through our gut undigested.
Eating a high-fiber diet is associated with a healthy weight, blood pressure, blood sugars, cholesterol and a reduced risk of having diabetes, heart disease, strokes, and breast or colon cancer (5).
According to the USDA Dietary Guidelines, “More than 90 percent of women and 97 percent of men do not meet recommended intakes for dietary fiber”.
So let’s learn more about why it’s so important and how to eat enough of it!
Insoluble vs. soluble fiber
There are two types of fiber – soluble and insoluble. Most plant foods contain both types in different ratios. Both types of fiber work together to promote healthy gut bacteria, metabolic health, and keep you fuller longer.
Soluble fiber
As it moves through your gut, it attracts water and forms a gel that helps to remove things like toxins, excess hormones, and cholesterol from your gut lining. It’s also very fermentable, which helps promote healthy gut bacteria (more on that below).
Insoluble fiber
This rightly named fiber stays intact as it moves through your gut. It helps to bulk up your stool and generally “move things along” more efficiently, if you will! This is the type of fiber that can help with constipation.
5 health effects of fiber
1. Keeps you regular
As I mentioned above, both types of fiber work together to bulk up and soften your stools so that they are easier to pass, decreasing your chance of constipation and related conditions (like hemorrhoids!).
2. Promotes healthy gut bacteria
Your gut bacteria feed on fiber, so if you’re eating lots of high fiber foods, your gut bacteria are very happy and this helps promote a diverse gut microbiome (meaning a good balance of different good bacteria in your gut) (1).
When fiber is fermented in your gut, it produces molecules called short-chain fatty acids. Studies show that higher levels of these molecules promote better insulin sensitivity and weight regulation (4).
Having a healthy gut microbiome plays an important role in how you absorb glucose, insulin sensitivity, and it helps reduce overall gut inflammation by promoting a healthy mucus lining.
3. Supports healthy cholesterol levels
When fiber enters your gut, it attracts water and forms a gel that helps to prevent cholesterol from getting broken down and absorbed into the bloodstream (5,7).
Related: Cholesterol 101, What is the real cause of heart disease?, Everything you need to know about diet, cholesterol, and heart health
4. Keeps you satiated and regulates appetite and weight
Since fiber adds bulk to your stools and slows down “gastric emptying”, this helps you feel fuller longer and regulates appetite. It also helps with maintaining a healthy weight because if you have lots of high-fiber foods in every meal, you’ll likely eat less of other more calorically dense foods. Just don’t skimp on the protein!
Related: How much protein you actually need
5. Balances your blood sugar
Eating a high fiber diet helps to reduce the spike in blood glucose that happens after eating a meal (2). Soluble fiber slows down the digestion of nutrients, which delays the absorption of sugars/carbohydrates into your bloodstream.
Studies have shown that a diet high in fiber (~35g) significantly reduces your risk for type 2 diabetes (3).
How much fiber do you need?
Recommended ranges for fiber range from 25-50+g per day. As a general rule of thumb, aim to get at least 30 grams of fiber per day. The higher your fiber intake, the greater the beneficial effects it will have on your metabolic health (reduced LDL, improved satiety, blood sugar regulation, etc…).
Since soluble fiber attracts water, you want to make sure you’re drinking plenty of it when eating a high-fiber diet.
Also, if you want to increase your fiber intake, do it slowly so that your gut can adapt. Introducing too much fiber all at once can cause intestinal discomfort (gas, bloating).
Where to find fiber (soluble vs. insoluble)
High fiber foods include fruits, veggies, whole grains, legumes, nuts and seeds. See the table below with a list of specific high fiber foods, organized by category.
You’ll notice a lot of overlap since most plant foods have both types of fiber, just in different ratios. So don’t get hung up on soluble vs. insoluble! The best way to make sure you’re getting both types of fiber is to just incorporate a variety of the above mentioned food groups into your diet.
| Soluble fiber | Insoluble fiber |
| oats beans/legumes ground flaxseed apples, bananas (unripe) citrus fruit berries carrots peas avocado ground psyllium (usually taken as a supplement) | whole-wheat flour whole grains nuts ground flaxseed chia seeds beans/legumes cauliflower green beans potatoes carrots avocado |
How to eat enough fiber every day
As mentioned above, if your meals and snacks include a variety of high fiber foods, you’re in good shape! Below is an example of what 30g of fiber looks like in one day:
- Breakfast: 1/2 cup oats + 1 tbsp chia + 1/2 cup fruit (~12g)
- Lunch: includes 1 cup cooked veggie + 1 cup cooked grains (~9g)
- Dinner: includes 1 cup cooked veggie + 1/2 cup beans (~10g)
- Snacks! Get another 5-10g of fiber by including fruits/veg/nuts/beans/seeds in your snacks.
It’s really easy to sneak fiber into your breakfasts by adding nuts/seeds and fruit to your smoothies or oats.
When it comes to lunch and dinner, just try to include a variety of veggies, beans, whole grains, and nuts/seeds. I love leaning on frozen veggies and canned beans as a quick and easy way to add fiber to any meal.
Snack on a handful of nuts or seeds or Greek yogurt topped with fruit, etc… for an easy fiber boost.
To get a better grasp on how much fiber you can find in foods per serving, reference the table below (assume all veggies are cooked).
| Amount of fiber in food per serving | Amount of fiber in food per serving |
| 1/2 cup dry oats = 4g 1/2 cup beans/legumes =6-8g 2 tbsp ground flaxseed = 6g 2 tbsp chia seeds = 10g 1/4 cup almonds = 3.5g 1/4 cup pumpkin seeds = 5g 1 apple = 4g bananas (unripe) = 3g 1 orange = 3g 1/2 cup raspberries = 4g 1/2 cup blueberries = 1.8g 1/2 avocado = 5g1/2 cup peas = 4g | 1/2 cup cauliflower = 1.7g 1/2 cup kale = 2.8g 1/2 cup broccoli = 2.6g 1/2 cup green beans = 1/7g 1/2 spinach or kale = 2.2g 1 medium potato (with skin) = 4.7g 1 carrot = 2g 1/4 cup whole-wheat flour = 3.3g 1 cup cooked brown rice = 3.5g 1 cup cooked quinoa = 5g 1 cup cooked farro = 6g 1 tbsp ground psyllium = 7g |
The main takeaways!
Don’t get hung up on the type of fiber or counting how much fiber you’re eating every day.
I just wanted to make you aware of why it’s important to eat plenty of daily fiber – the more fiber you eat, the better (30-50g, so long as you can tolerate it). Include high fiber foods in your meals and snacks most of the time.
If you’re cooking along with the Cooking Club menus and following that general eating philosophy, then you are in good shape!
Resources:
- https://academic.oup.com/nutritionreviews/article/59/2/52/1826089?login=false
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5390821/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872693/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4472947/
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7146107/
- https://www.health.harvard.edu/blog/fiber-full-eating-for-better-health-and-lower-cholesterol-2019062416819
- https://www.levels.com/blog/why-fiber-is-essential-to-metabolic-health
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