If you’re ready to increase the amount of fiber in your diet, that’s a positive step. You’ll want to follow these guidelines to help you reap the benefits but avoid the side effects of overdoing it.
By Madeline Vann, MPH
Medically reviewed by Lindsey Marcellin, MD, MPH
A popular TV commercial shows a woman eating broccoli and other fiber-rich foods throughout the day, depicting how difficult it seems to get the recommended daily levels of fiber. In truth, a lot of people just don’t bother. Yet to the other extreme, it’s possible to get too much fiber or eat too much at once, which can lead to unpleasant side effects.
Too much fiber
So just how much fiber do you need? The national fiber recommendations are 30 to 38 grams a day for men and 25 grams a day for women between 18 and 50 years old, and 21 grams a day if a woman is 51 and older. Another general guideline is to get 14 grams of fiber for every 1,000 calories in your diet. Achieving these goals is beneficial to your overall health, and fiber helps you feel fuller longer.
For many people, it can be a challenge to get that much fiber in a typical American diet. Most people top out at an average of 15 grams per day, regardless of how many calories they eat. But if you’re going overboard with a high-fiber diet plan, you could be putting yourself at risk for problems like stomach cramps, constipation, and even nutritional deficiency.
“High levels (of fiber) can also interfere with absorption of some minerals, such as iron, and some antioxidants, such as beta-carotene. It’s rare, though, for people in this country to be getting too much fiber,” says registered dietitian Brie Turner-McGrievy, Ph.D., R.D., of the University of North Carolina at Chapel Hill.
Getting the Right Amount of Fiber
Of course, it’s possible to feel like you’re getting too much fiber, either because of how you’re eating your fiber, or because you’ve dramatically increased your fiber intake too quickly. Here are some tips for getting more fiber without unpleasant side effects:
Space out portions. “Spreading out your fiber intake throughout the day will allow you to avoid some of the gastrointestinal discomforts that a large amount of fiber may present,” says Dr. Turner-McGrievy. Try to include fiber-rich foods in every meal and snack, but don’t feel like you have to overdo it.
Increase slowly. A new commitment to healthy eating could make you want to achieve those daily fiber goals quickly, but when it comes to ingesting fiber, it’s a good idea to take your time. You want to give your gut the chance to get used to the new amounts of fiber you’re eating. This will decrease some of the digestive side effects you see with a sudden increase, Turner-McGrievy says. Plan to take about two weeks to reach your goal, and pay attention to discomfort along the way. If you do experience any discomfort, it may be a sign that you shouldn’t add any more fiber just yet.
Hydrate. Fluid and fiber go hand in hand: The more fiber you eat, the more fluid you need. “We need to make sure we drink an appropriate amount of water along with our fiber intake to allow for proper digestion,” says Turner-McGrievy. Remember that juices, soups, and other liquids count.
If your diet is largely made up of whole foods, including lots of vegetables, beans, fruits, and whole grains, you could easily meet or even slightly exceed the daily recommended fiber intake. But fiber intake isn’t necessarily a “more is better” situation once you’ve met the daily requirement. Taking significantly more fiber than is recommended won’t magically improve your health, and could actually make you feel worse.