When it comes to nutrition, fiber often takes a backseat to protein, fats, and vitamins. But if you’ve ever been told to “eat more fruits and vegetables,” it’s largely because of the fiber they contain. Fiber is a type of carbohydrate found in plant foods – but unlike regular carbs, our bodies can’t digest it fully. Instead, it passes through the digestive system, doing a lot of good along the way.
Fiber is often described as the unsung hero of a healthy diet. It doesn’t just keep things moving in your gut – it plays a critical role in regulating blood sugar, supporting heart health, and even helping with weight management. And yet, despite these benefits, most of us don’t get nearly enough of it.
What Exactly Is Fiber?
Fiber is the part of plant foods – fruits, veggies, grains, and legumes – that your body can’t break down. While your stomach enzymes can’t digest fiber, your gut bacteria can. This fermentation process produces short-chain fatty acids that can be absorbed. Some fibers even help inhibit some fat absorption, potentially resulting in negative caloric effects.
Types of Fiber – Why Both Matter?
Fiber comes in two main types, and they each play a different role in the body:
Soluble Fiber
This dissolve in water, forming a gel-like substance in your stomach. It slows down digestion, which can help regulate blood sugar, and keep you fuller for longer. Soluble fiber is found in oats, beans, lentils, fruits, and some vegetables.
Insoluble Fiber
This doesn’t dissolve in water and adds bulk to your stool, helping food move through your digestive system more easily. It’s essential for preventing constipation and promoting regular bowel movements. Whole grains, nuts, and many vegetables are great sources of insoluble fiber.
Most plant-based foods contain a mix of both types, which is why variety is key.
How Much Fiber Do You Actually Need?
There’s no single “perfect” amount, but a good rule of thumb is 14 grams of fiber for every 1000 calories you eat. For someone consuming around 2500 calories a day, that translates to about 35 grams of fiber.
Interestingly, while we often worry about eating too little fiber, there’s no official upper limit for how much you can safely consume – as long as the fiber comes from whole foods like fruits, vegetables, and grains.
In fact, the Academy of Nutrition and Dietetics highlights that:
“Although excessive fiber intake has been linked with adverse gastrointestinal events, these effects have been seen with certain functional fibers, as opposed to dietary fiber. Vegetarian diets may provide >50 g fiber/day, and high intakes of dietary fiber have not been confirmed to cause adverse health effects in adults, as demonstrated by the lack of Tolerable Upper Intake Level. Little work has been conducted in this area since the last position article was published.”
Is Soluble or Insoluble Fiber Better?
You might wonder if one type of fiber is better than the other. The truth is, both are important. Research shows that soluble and insoluble fiber offer similar health benefits, and one isn’t necessarily superior.
For example, both types have been linked to a lower risk of colorectal cancer, improved heart health, and better overall longevity. So instead of worrying about hitting a perfect balance, just focus on getting fiber from a variety of foods.
Is There an Ideal Balance Between Soluble and Insoluble Fiber for Optimal Health?
No, there isn’t a specific ratio of soluble to insoluble fiber that you need to aim for.
Most fiber-rich foods naturally contain a mix of both types, so as long as you’re eating a variety of fruits, vegetables, whole grains, and legumes, you’re covered.
Common High-Fiber Foods to Include
- Fruits – Apples, oranges, berries, and pears
- Vegetables – Broccoli, carrots, spinach, and peas
- Whole Grains – Oats, quinoa, brown rice, and whole-wheat bread
- Legumes – Lentils, chickpeas, and black beans
- Nuts and Seeds – Almonds, chia seeds, and flaxseeds
The Bottom Line
Fiber may not seem glamorous, but it plays a huge role in supporting overall health. Whether your goal is to improve digestion, manage your weight, or reduce the risk of chronic disease, fiber should be a key part of your diet.
Instead of obsessing over the exact balance of soluble and insoluble fiber, focus on eating a wide variety of plant-based foods. Your body – and your gut – will thank you.
Reference:
Grabitske, Hollie A., and Joanne L. Slavin. “Gastrointestinal effects of low-digestible carbohydrates.” Critical reviews in food science and nutrition 49.4 (2009): 327-360.
Dahl, Wendy J., and Maria L. Stewart. “Position of the Academy of Nutrition and Dietetics: health implications of dietary fiber.” Journal of the Academy of Nutrition and Dietetics 115.11 (2015): 1861-1870.
Xu, Xin, et al. “Associations between dietary fiber intake and mortality from all causes, cardiovascular disease and cancer: a prospective study.” Journal of translational medicine 20.1 (2022): 344.
Arayici, Mehmet Emin, et al. “Soluble and insoluble dietary fiber consumption and colorectal cancer risk: a systematic review and meta-analysis.” Nutrition and Cancer 74.7 (2022): 2412-2425.
