Some foods with the highest fiber content for adults include apples with skin, bananas, oranges, strawberries and raspberries, according to WebMD. Other high-fiber foods include lentils, beans and potatoes. Dark vegetables such as carrots, beets, broccoli, artichokes and spinach also contain high amounts of fiber.
Some examples of grains that are high in fiber include barley, rye flour, wheat bran, spelt and millet, states BodyBuilding.com. Other grains high in fiber are steel-cut oats and buckwheat groats. Eating plain popcorn that hasn't been buttered or salted is also a healthy way to increase fiber intake. Nuts and seeds are also valuable sources of fiber, and some of the best sources include chia seeds, hemp seeds, ground flaxseed, almonds and pistachios. Coconut in flour or in dried form is also high in fiber.
Fiber helps food move more quickly and efficiently through the digestive tract, states Mayo Clinic. People who eat diets high in fiber are also less likely to develop heart disease, obesity and diabetes. Doctors recommend that women consume 21 to 25 grams of fiber per day, while men should consume 30 to 38 grams a day. The fiber content of foods can vary between different brands and the size of the food itself.