There's a reason packaged foods advertise high fiber counts on the wrapper. After all, fiber's benefits include promoting gut health, regular digestion and steady blood sugar levels. But you can have too much of a good thing, which is why you may need to watch for signs you've eaten too much fiber.
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- Fruits and vegetables
- Whole-wheat flour
- Legumes like lentils, peas and beans
- Oats and oatmeal
Most people don't get enough of this nutrient in their daily diet. Nonetheless, it is possible to overdo it, especially if you're regularly snacking on high-fiber bars or taking a supplement.
So, what happens if you take too much fiber? Keep an eye out for these four symptoms of fiber overload (and what to do to avoid side effects of too much fiber in the future).
1. You're Feeling Bloated or Gassy
A little bloating and gas is normal when you eat a fiber-heavy meal, especially if it involves cruciferous veggies like cauliflower or Brussels sprouts, says dietitian Bonnie Taub-Dix, RD, author of Read It Before You Eat It: Taking You from Label to Table. But if your symptoms cause discomfort or disrupt your day-to-day, you may be overdoing it.
Fiber is a carbohydrate you can't digest, according to the Harvard T.H. Chan School of Public Health. Instead, it goes through your body unprocessed. As a result, you can feel overly full or gassy as the nutrient moves through your system.
You may also have gas and bloating if you're increasing your day-to-day fiber intake too quickly, Taub-Dix says — in other words, you can have too much fiber at once. While you may only be eating the recommended daily amount (which is 21 to 38 grams, depending on your age and sex), going from 10 grams one day to 30 grams the next is likely to cause digestive issues.
The fix? Because you can eat too much fiber too fast, ease into it at first. Gradually work the nutrient into your diet over the course of a few weeks to give your body time to adjust, according to the Mayo Clinic.
2. You're Constipated
There are two types of fiber out there: soluble and insoluble. Soluble fiber, found in oats, nuts and beans, dissolves in water and helps control blood sugar levels, keeping you full throughout the day, according to the Harvard T.H. Chan School of Public Health.
Insoluble fiber, found in wheat and legumes, helps move food through your digestive system, promoting regularity in the bathroom.
But eating too much fibrous food like oatmeal or whole-wheat cereal can have side effects: If you're not drinking enough water, these fibers can produce rather than prevent constipation.
How to Relieve Constipation From Too Much Fiber
If you're constipated because you took too much fiber, you may need to up your H2O, Taub-Dix says. She suggests sipping at least one tall glass of fluid at each meal.
Getting enough exercise is another method to help relieve the side effects of overeating fiber, including constipation. Moving daily helps increase the muscle activity around your intestines, which can encourage normal bowel movements, according to the Mayo Clinic.
3. You're Feeling Abdominal Pain
Increasing your fiber too quickly can also cause your stomach to cramp and feel distended or even painful, according to the Mayo Clinic.
Usually stomach cramping or a bloated belly will go away once your body digests and passes the fibrous foods you ate, Taub-Dix says. Increase your overall fiber across the span of a week or two (instead of all at once) and these symptoms of too much fiber will most likely go away.
But if you continue to feel pain digesting high-fiber foods, talk to your doctor or a dietitian. They can help you figure out which food your body isn't loving.
Also, you don't want to confuse a little extra bloating with weight gain, Taub-Dix says. High-fiber foods like fruits and vegetables are high in nutrients and low in calories, so the last thing you want to do is cut them from your diet due to a little bloat.
"If you have too much fiber in your diet and your abdominal area feels distended, that doesn't mean you gained weight," Taub-Dix says. "This is not fat, it has nothing to do with fat. This is just bloat because of the processing of carbohydrates in your body, which could sometimes cause air bubbles."
Drinking plenty of water or sipping some tea is a great way to help soothe a cramped stomach, Taub-Dix says.
4. You Have Loose Stools
Although it's rare, eating too much fiber can sometimes cause diarrhea or loose stools, Taub-Dix says. This is more common if you take too many fiber supplements (like gummies) or eat a lot of fiber-fortified foods (think snack bars and breakfast cereals).
"When you try to increase your fiber intake too fast and you're not used to it, it can cause this side effect," Taub-Dix says. "If that's the case, make sure you're drinking enough fluid to stay hydrated and ease up on the fiber for a day or two until your system calms down."
Fiber Supplements and Medication
It's generally safe to eat fibrous foods when you take your medication, according to Harvard Health Publishing. But when it comes to supplements, it's best to take medicine two or three hours before or after your fiber pill.
That's because fiber supplements act like a broom in your digestive tract, and may sweep out your medication before it has the chance to absorb.
It's also important to remember that the FDA does not require supplements to be proven safe or effective before they are sold, so there’s no guarantee that any supplement you take is safe, contains the ingredients it says it does or produces the effects it claims.
How Much Fiber Should You Get Per Day?
Thanks to some of today's popular diet fads (looking at you, keto diet), most people aren't actually eating enough fiber. But as you may have experienced firsthand, it's also possible to eat too much fiber and have negative effects.
Generally, Americans eat about 10 to 15 grams of fiber per day, according to Harvard Health Publishing. Here's a look at how much adults should actually be getting, broken down by age and sex:
How Much Fiber to Eat Each Day
People Assigned Male at Birth
People Assigned Female at Birth
50 and Younger
Older than 50
- Harvard T.H. Chan School of Public Health: "Fiber"
- Mayo Clinic: "Constipation"
- Mayo Clinic: "Water: How Much Should You Drink Every Day?"
- Harvard Health Publishing: "Should I be eating more fiber?"
- Mayo Clinic: "Dietary Fiber"
- Harvard Health Publishing: "By the way, doctor: Will a fiber supplement interfere with my medications?"
- FDA: “FDA 101: Dietary Supplements”