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.
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.
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.