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How to Eat More Fiber — and Why You Should with Dr. Carolyn Newberry

A gastroenterologist shares the importance of fiber in a healthy diet and ways to make sure you're getting enough.

How to Eat More Fiber — and Why You Should with Dr. Carolyn Newberry

A gastroenterologist shares the importance of fiber in a healthy diet and ways to make sure you’re getting enough.

This week, our host Faith Salie talks to Dr. Carolyn Newberry, a gastroenterologist at NewYork-Presbyterian and the director of the Gastrointestinal Nutrition Program at Weill Cornell Medicine, about the importance of fiber and why we need more of it than we may think. She also provides helpful tips on how to incorporate fiber into your diet.

Episode Transcript

Welcome to Health Matters. Your weekly dose of the latest in health and wellness from NewYork-Presbyterian. I’m Faith Salie.

Did you know there’s a carbohydrate that is essential to a healthy diet?  

That carb is fiber. 

This week we’re talking with Dr. Carolyn Newberry, a gastroenterologist at NewYork-Presbyterian and the director of the Gastrointestinal Nutrition Program at Weill Cornell Medicine. 

She breaks down the importance of fiber, including how much we should be eating and easy ways to incorporate fiber into our diet

Faith: Hi Dr. Newberry. Thank you so much for joining us.

Dr. Newberry: Thank you.

Faith: So this week we want to learn about fiber, and I would love to get really fundamental with you. What is fiber?

Dr. Newberry: So fiber is a carbohydrate source. It’s a matter that’s made from vegetables and fruits and natural types of foods that is indigestible, actually, by the human body. And so it is something that when you eat it, it helps things like bulking stool, making it easier to pass and really has a lot of additional health benefits because it just basically keeps things moving in the body.

Faith: Conventional wisdom would tell us that something that’s indigestible is probably not something we should eat. And yet fiber is absolutely essential.

Dr. Newberry: Right.

I completely agree that it, it kind of sounds funny that we don’t actually have the enzymes to break this type of substance down. 

But the reason why it is so important is that it actually keeps the pipes of the digestive tract moving and flowing. And so it keeps things so that there’s less pressure on the walls of the digestive tract.

So, yes, we don’t actually physically break it down, but, but it’s a super important part of our health and, and what we should be eating.

Faith: Is fiber kind of undersung? 

Dr. Newberry: There are so many different things in nutrition that we focus on. And the things that we’re really excited about over time change. But I think fiber consistently is something that should stay in the spotlight. And the reason for that is because it is something that is really a marker of the amount of fruits and vegetables and unprocessed grains and things that we’re eating, all of which have their own health benefits, both from the fiber content and the other nutritional components of those foods.

And so yes, I completely agree that, that we shouldn’t forget about fiber.

Particularly as a gastroenterologist, this is something I probably counsel almost all of my patients on, regardless of what their medical history is.

Faith: I feel like long ago someone told me fiber kind of acts like a brush, as it as it goes through our colon, and that really stuck with me. That made sense to me. Is that a useful metaphor, do you think?

Dr. Newberry: Yeah, I mean, I think that is a good way to think about it. 

You know, fiber comes in a couple different subtypes.

The soluble type of fiber, which is the type that dissolves in water. It’s almost like a sponge, that when you have plain oatmeal, for instance, you throw it in a bucket of water, it kind of spreads out to fill the shape of the bucket. And that’s kind of the way that we think about it. And so that type of fiber really draws in water, helps the stools be bulky and clean the walls of the colon almost as it goes through.

And then there’s this insoluble fiber type that’s more of like a roughage type fiber. So that’s a piece of celery, you throw it in a bucket of water, it doesn’t change shape. It has more of those fibrous strands, those fibrous tissues in it. And that really, in addition to the soluble fibers sucking up the water, It helps make the bulk of the stool itself bigger and heavier and more formed and something that again can more easily pass through the digestive tract.

So I think it’s a good way to look at it.

Faith: Is one more beneficial than the other when it comes to soluble versus insoluble.

Dr. Newberry: They’re both important in the diet. As you can imagine, the health benefits of eating a plain bowl of oatmeal, maybe with some like chia seeds or flax seeds in there, which has like a ton of soluble fiber content, are going to be different than eating, you know, that big green salad. But they’re all important as part of a balanced diet.

And so I don’t want to say the plain cup of oatmeal is any healthier or less healthier than the salad. It’s all about having variety in the diet. It’s about eating enough colors, it’s about eating enough different sources of types of fibers so that these things can all work together to improve your digestive health.

Faith: What do you think would surprise people the most to learn about fiber?

Dr. Newberry: I think it would surprise people and many of my patients are surprised when I explain to them what a small percentage of the population actually gets the recommended daily allowance of fiber. So they quote something like, 95% of Americans are not meeting the recommended fiber goals. And so those goals are about 25 to 35 grams of fiber per day on average.

Faith: Just so we could get an idea of that in our brains, how many apples would that be?

Dr. Newberry: An apple’s about four grams of fiber. So, so yeah — so maybe eight apples.

Faith: Wow, okay. That’s instructive.

Dr. Newberry: Yes. And I would recommend people to get different sources of fiber and not eat eight apples a day. But, but that sort of gives you an idea.

Faith: ​I did think that’s what you might answer is that the most surprising thing to learn about fiber is how much of it we need.

Dr. Newberry: Yes. I think one of the reasons why we don’t necessarily meet these goals most of the time is just the way that the American diet has sort of evolved, where we are eating a lot of quick foods, processed foods, things that have sort of taken the fiber out of them.

You know, your best sources of fiber are fresh fruits and vegetables, which are sometimes hard to access and hard to like eat on the go. You’re busy. And they may not be the food of choice at any particular time.

Faith: Can we kind of drill down on some of this dietary stuff?

Well cause you’re here, cause I get to ask you, so for example, is whole wheat bread, a whole grain?

Dr. Newberry: So we would absolutely consider whole wheat bread, a whole grain depending on what the ingredient list says. So sometimes it’s a little tricky because the food industry I think has a lot of liberties with the way that they advertise things and the way that they label things.

And so what you really want to look for, Is two things on the label. So the first is I would look at the first ingredient on that bread. And so ideally it’s whole wheat flour as opposed to wheat flour, because sometimes white bread will be labeled like white whole wheat or something like that. And then it actually doesn’t have whole grain as like the first ingredient list.

And the other thing you can look at is, is the fiber content of the bread. The ratio of fiber is often really important. And the way you can calculate that is, is the number of carbohydrates total in a food, dividing it by the amount of fiber that’s in it.

And so this is all in grams. So to give you an example if a product has 10 grams of carbohydrates and five grams of those are fiber, that’s a two to one ratio, which is a really good ratio. Anything less than five to one is really good. And higher numbers, we sort of wonder about the content of whole grain in them.

Faith: Okay, so I’m going to make a confession here. Dr. Newberry, I look at labels pretty often, and a lot of times I’m thinking, okay, how much sugar does this have? And I don’t look for fiber, but fiber is always going to be listed on a nutritional label?

Dr. Newberry: Yes. So it should always be there. It’s like underneath, sort of where you’re seeing the amount of carbohydrates.

The three types of things you’re going to be looking at in the carbohydrate space would be the total carbohydrates of the product, the fiber of the product, and the sugar of the product.

Faith: How can someone tell if they’re lacking in fiber? What are some of the symptoms of a fiber deficiency?

Dr. Newberry: So oftentimes it starts with digestive symptoms and what people often experience is that they get constipated. So they get backed up because if they don’t have enough fiber in the stool itself, then then it doesn’t move as well through the digestive tract. And that can also in turn, cause things like bloating, abdominal distension, abdominal pain.

If people get backed up, they can get nauseous. So it’s really, a number of different digestive problems that, increasing your intake of fiber can actually be really helpful for.

Faith: Is it possible to have too much fiber?

Dr. Newberry: Because fiber is indigestible, it’s going to be excreted by the body. So this idea that you could get too much fiber, that would be dangerous to your health. It’s pretty uncommon. 

The only people that really need to watch fiber where it actually could cause health problems would be if you have history of, of surgery on your digestive tract and that has caused significant narrowing of the digestive tract or there’s like a lot of inflammation in your digestive tract because you have a digestive condition like Crohn’s disease or something.

I think the biggest thing that people experience when they start adding fiber is that, especially if your body is not used to eating a lot of fiber, many people feel like bloated and distended at first because your body has to almost like up-regulate the way that it processes the fiber and it, and it’s good to sort of do it in a gradual process.

I always say everybody’s body is different in how it responds to the foods that it eats. And so you have to know your body and you have to play around with these things. But some fiber, high fiber foods also produce gas in some people and so you may just have to adjust the types of fibers you’re eating. Not that you shouldn’t eat fiber, but just you have to work with somebody to figure out what works best for your body. And that’s where a dietician really comes into play. And we work very closely with our dieticians in clinic.

 Also, I know there’s been a lot of buzz about these new medications to help with weight loss and to help people control blood sugar levels better, you know, Ozempic and Wegovy and these different drugs and those drugs work so well because they slow everything down and they make people feel full for longer.

But because of that, people, especially when they first start the medication or are going up on a medication dose, they may not tolerate like a big salad, for instance, at the beginning because they’ll get really nauseous because it just doesn’t drain very well. Because everything has been slowed down. 

Faith: As someone decides to incorporate more fiber in their diet, are there certain foods that make sense to start with first?

Dr. Newberry: So I really love plain oatmeal because you can add things to it to increase the fiber content, but you can still just eat it plain, add a little cinnamon to it, you know, make it either with milk or with water. That is a good source of plain soluble fiber that generally causes not too much bloating.

Another good example is brown rice. I mean you always have to watch portions with all of this of course. But, brown rice with some cooked vegetables are a good way to get like, different sources of fiber that probably is tolerated well by the body. 

And then sweet potatoes, as well. So sweet potatoes have a lot of vitamin A, you know, they’re very bright colors, so they have a good nutritional content and then there’s lots of great ways to prepare them. They taste good. They have that natural sweetness to them, and they have a high source of fiber.

Faith: When someone wants to just kind of pick up a quick and easy snack and on the go kind of thing, and you are being fiber-conscious, what’s a great thing to grab?

Dr. Newberry: I think a handful of nuts is a good option. If you are tolerant of nuts. So it can be peanuts, it could be cashews, it can be almonds, it could be pistachios, whatever you like to eat. 

Faith: This is a selfish question because this is possibly my favorite food. Where does popcorn fall on the fiber scale? 

Dr. Newberry: Plain popcorn could be a good option. It tastes good. It is a good source of fiber and can help you feel full. 

You know, other good things they, you may have packages of nut butters. Now, you know, you get little almond butter packs or little peanut butter packs. You could eat with some carrots or some celery, or a couple whole wheat crackers, you know, so you can have that on the go, so I think those are three places to start.

Faith: So just because something is smooth, nut butter is just as good as nuts when it comes to your fiber intake.

Dr. Newberry: Yeah, I mean, I think you need to think of how the food is processed. So like I always give the example of like a smoothie versus juice. So we know that a fruit has a lot of good fiber content in it. But a juice actually takes much of the fiber portion out of it.

You know, if you think of a juicer, you have all that like residue left at the end.

Faith: That’s the good stuff!

Dr. Newberry: Yeah, that’s the good stuff, right? So it only pulls out the liquid, which is all the sugar, honestly, which is why the juices taste good and it doesn’t have the fiber mixed with it.

It’d  be better if you threw it into the blender and you get the whole fruit and you get everything that comes with that.

So the same thing with nuts and nut butters. You know, if the nuts are just being broken down to a smooth paste, but the whole content of the nuts is there, it’s going to have the same nutritional value. 

Whether you eat it puree or you eat it in its whole form, as long as it’s all there and they’re not taking a part of it out, it’s still going have the same health benefits.

Faith: Talk to me about fiber supplements. Are they effective?

Dr. Newberry: Yes. So, we also often recommend people take fiber supplements if they are not meeting their daily goals. Now I always put that caveat in terms of the scientific literature out there and the health benefits of fiber supplements, it’s much weaker than getting fiber from dietary sources but particularly for digestive symptoms, you know, if you’re really constipated, you can try to push fiber in your diet. But you may also benefit from reaching goals through fiber supplementation. 

So there’s a lot of different products on the market that you can get fiber from. You know, there’s powders, there’s capsule formulas there’s gummies. If you need an extra five grams of fiber, you know, this is a good way to sort of add that to sort of meet the overall goal of the day.

Faith: What are your recommendations for balancing fiber with our other nutritional needs, like proteins and healthy fats?

Dr. Newberry: Yeah, so, the example of something like nuts where they are a good source of protein and they’re a good source of fiber. You know, this is a power food. 

When you’re picking a snack or you’re picking a meal, make sure you’re representing multiple food groups, multiple colors, etc, on the plate. 

You know, the piece of chicken for your protein. You have some quinoa for the grain, which also has some additional protein in it and some fiber in it. And then you pick some sauteed carrots or something, and you are able to sort of get those balanced calories.

Faith: I really love how you informed us that fiber is a carbohydrate. I feel like it’s an essential part of rebranding carbohydrates who, who have been vilified for so long.

Dr. Newberry: Yes, I mean, I think carbohydrates get a bad rep. For whatever reason, but there are different, lots of different types of carbohydrates. And actually if you’re eating a food that’s higher in carbohydrates, but much of that carbohydrate comes from fiber, the nutritional value of it is actually quite good.

Faith: How can fiber improve our overall health?

Dr. Newberry: So in addition to digestive health, which is sort of been a take home message, fiber can help regulate secretion of insulin, which regulates our blood sugar levels. So it can have added benefits of people that have problems with blood sugar, like people with diabetes.

And it can reduce risk of heart disease and strokes and things that may be related to some of those problems with blood sugar that damage blood vessels and can cause things like plaque buildup. So it is a good way to try to reduce your risk of developing further progression of disease.

Faith: Dr. Newberry, thank you so much for breaking this down as it were for us today.

Dr. Newberry: Thank you so much for having me and discussing this important topic.

Our many thanks to Dr. Carolyn Newberry.

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