Fiber may help you lose weight and live longer. Here are 5 mistakes that stop most people from getting enough, according to a dietician — and how to fix them.

• Fiber is essential for gut health, weight loss, and may even help people live longer.
• Most Americans only eat 10-15 grams of fiber per day on average, which is half the recommended amount.

Eating enough fiber is essential to gut health, and may even be one of the secrets to a longer life.

In the Blue Zones, areas of the world where people routinely live longer and healthier lives, fiber-rich foods like beans, nuts and seeds, whole grains, and root vegetables are all a major component of their diets.

Some types of soluble fiber, like psyllium husk, can also potentially aid with weight loss by helping you feel full — though it may lead to a binge hours later if you're not getting enough nutrients.

Yet while men should be aiming for 38 grams of fiber a day and women 25 grams of fiber a day, only 7% of Americans get enough fiber in their diet, according to the American Society for Nutrition.

Insider spoke to Dr. Joanne Slavin, a professor in the department of food science and nutrition at the University of Minnesota, and a registered dietitian, about common mistakes people make when it comes to getting fiber in their diet — and how to fix them.

Mistake #1: Cutting out carbs

Diet culture is partially to blame for Americans' low fiber intake, Slavin told Insider.

"For a lot of people, carbs are the enemy because of calories," Slavin said. But "fiber is a carbohydrate and it tends to hang with other carbohydrates." Thus by cutting carbs, Slavin said, people inadvertently cut out fiber.

In America especially, foods with whole grains — like breads, pasta and rice — tend to be the most accessible source of fiber, Slavin said. But these are the foods that are often first to go in a low carb diet.

Rather than cut out carbs, opting for whole grain foods — like whole wheat bread — can boost fiber intake, and support gut health. Leaving carbs in the fridge overnight can also turn them into resistant starches, a higher-fiber food.

Mistake #2: Assuming fruit is a good source of fiber

One of the main misconceptions people have about fiber is that fruit is a good source, said Slavin.

"They go 'ah fruit it's just loaded with fiber,'" said Slavin. But "generally it's not." Fruit contains primarily water and sugar, but not much fiber, she said.

"Most fruits have maybe one to three grams of fiber," Slavin said.

Although most fruits don't have a lot of fiber, there are some exceptions. Raspberries contain about 8 grams of fiber per cup, and blueberries contain about 5 grams per cup.

Mistake #3: Eating a leafy salad with no toppings

While a salad can be a very healthy meal choice, it isn't necessarily high in fiber. Similarly to fruit, salad greens contain mostly water.

"A serving of lettuce has maybe one to two grams of fiber," Slavin said. "If you can put some chickpeas, or put some nuts, or put other things you can increase that for sure."

Just a half cup serving of chickpeas has 6 grams of fiber, and one ounce of raw almonds has 3.5 grams of fiber, Insider reported previously.

Mistake #4: Giving up on fiber

People who aren't used to eating fiber may find that eating more fiber leads to a gastrointestinally unpleasant experience. But one of the biggest mistakes people can make is to give up on fiber, Slavin said.

Instead, she urges people to slowly incorporate more fiber into their diet. She also recommends trying different sources of fiber. "If somebody says I tried this product, it really bothers me, well try something else," Slavin told Insider previously.

Mistake #5: Opting for supplements like prebiotic sodas over whole foods

Fiber supplements — including prebiotic sodas — have become increasingly popular. Prebiotics are a type of plant fiber, and many of these sodas claim that they'll boost gut health. Although foods fortified with fiber are not necessarily a bad thing, Slavin advises people to prioritize fiber from whole food sources when possible.

Slavin recommends trying to add in whole food sources of fiber to each meal, and said it's fine for those foods to be frozen or canned.

But getting some fiber is better than getting no fiber at all, she said.

"Do I like fiber in pop? No, it wouldn't be my first choice for fiber. Do I like fiber in snack foods? No, not really," Slavin said. "But compared to not getting fiber," Slavin said, "for certain people, it might be the best solution."