How to Increase Fiber Without Overloading on Calories
Many high-fiber foods are also high in calories. If you’re looking to increase fiber but keep calories under control, you want foods with a high fiber density.
Monica Reinagel, MS, LD/N, CNS
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How to Increase Fiber Without Overloading on Calories
Donna wrote recently with an interesting dilemma. In an effort to improve the health of her intestinal microbiome, she’s been trying to eat more fiber.
This is a totally solid strategy. One of the most effective ways to boost the population of beneficial bacteria in your gut is to eat more prebiotic foods. And prebiotic foods is just a fancy way of describing foods that are high in fiber. Although our bodies cannot extract any nutrition from fiber, the bugs in our gut can. When we supply more food for them, they thrive.
There have been some interesting studies comparing the intestinal population of Westerners with that of rural south Africans. Their typical diet contains about twice as much fiber as the typical American diet and a lot less animal protein and fat. And the composition of their guts is strikingly different, with much higher and more diverse populations of health promoting bacteria. Not surprisingly, these Africans have much lower risks of colorectal cancer and other conditions that are thought to be influenced in part by the population of your gut.
But even more interestingly, adopting a diet that’s lower in animal fat and protein and higher in plant fiber can quickly change the composition of your gut flora for the better. And the same is also true in reverse. Switching from a diet high in plant fiber to one that’s high in animal fat and protein can quickly change the makeup of your intestinal microbiome for the worse.
Not ready to give up cheeseburgers just yet? Even without cutting down on animal protein and fat, simply adding more plant fiber to your diet can have beneficial effects. So, Donna is trying to upgrade her fiber intake from the recommended 25 grams per day to something closer to 40 or 50 grams. However, she’s finding it difficult to reach that target without eating too many calories.
What is Fiber Density?
What Donna needs is a way of ranking foods not just by their fiber content but by their fiber density, or how many grams of fiber they provide per calorie. This approach is similar to ranking foods by their nutrient density or energy density. Foods with a high nutrient density provide a lot of nutrition for not that many calories. That’s useful if you’re trying to lose weight. Foods with a higher energy density, on the other hand, provide a lot of calories in a small amount of food. That can be useful if you need to take in more calories.
There’s a lot more on nutrition and energy density here, as well as a Nutrient and Energy Density grid that you might find useful.
But if you’re looking to maximize your fiber intake without blowing out your calorie budget, neither energy density or nutrient density does the trick. You want to consider foods according to their fiber density, or how much fiber they provide per calorie.
You can calculate a food’s fiber density by dividing the fiber by the calories. Foods with a higher fiber density provide more fiber for fewer calories. A cup of black beans, for example, has about 17 grams of fiber and 220 calories. It’s fiber density is about 8. A cup of cooked broccoli only has about 5 grams of fiber but also has less than 50 calories. Its fiber density is almost 12. Foods with a higher fiber density will help you increase your fiber intake without taking in too many calories.
You can use this quick and dirty calculation to compare any two foods. But I crunched the numbers on a few thousand foods for you. And here’s what I found.
Remember that you can quickly calculate the fiber density of any food by dividing the fiber grams by the calories.
As a rule, legumes will give you the most fiber per serving, with anywhere from 12 to 18 grams of fiber per cup. High fiber cereals, crackers, and breads will also give you a lot of fiber per serving. But because all of these foods are also relatively high in calories, they have single digit fiber density scores.
If it’s fiber density you’re looking for, make friends with those leafy greens. Beet, mustard, and turnip greens, chicory and endive all have fiber density scores of 15 or higher. Next on the list would be kale, berries, broccoli, green beans, and artichokes, with fiber density scores between 10 and 15. Most legumes fall between 5 and 10. Meanwhile, nuts, seeds, whole grains, and cereals generally have fiber density scores of less than 3, meaning you’ll have to take in a lot of extra calories to take in much fiber.
Here’s a table of healthy foods ranked according to their fiber density.
Although you probably won’t see fiber density on Nutrition Facts labels or diet tracking software anytime soon, remember that you can quickly calculate the fiber density of any food by dividing the fiber grams by the calories. A fiber density of ten or more signals a food that delivers a lot of fiber without many calories.
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About the Author
Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes’ most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation’s leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.