Fiber

Fiber in vegetables, fruits, beans, and whole grains helps with digestion, weight loss, heart health, and cancer prevention. It can even increase your life span. Meat and dairy products contain no fiber—it’s found only in plant foods.

The Two Types of Fiber

Soluble fiber: Dissolves in water to form a gel. This gel is then easily digested by the bacteria in our guts and helps to promote a healthy gut microbiome.¹ When soluble fiber is fermented in the large intestine, it increases certain hormones that promote satiety, or a feeling of fullness, which is why high-fiber diets may help with weight loss.² Soluble fiber also increases the excretion of cholesterol in the stool and can help to lower total and LDL cholesterol in the blood.³

Insoluble fiber: Does not dissolve in water and passes through our guts mostly intact. Insoluble fiber bulks up our stool, helping to prevent constipation.³ This has two main benefits: First, it reduces the time that the lining of our gut is in contact with potential cancer-causing compounds in our food. Second, it traps fat molecules in the gut, reducing the number of calories absorbed from the food we have eaten, which can help with weight loss.

Plant-based foods contain a combination of both of these types of fiber, and the proportion of each may vary based on the food. While most people get only 10 to 15 grams of fiber a day, we recommend at least 40 grams per day for gut and metabolic health.

Heart Health

Fiber plays an important role in keeping our circulation and heart health strong. One important way this happens is through removing excess cholesterol through the digestive tract, as mentioned above. A pooled analysis of 10 cohort studies in the United States, including more than 300,000 people, found that those who ate more fiber had a lower risk of having a heart attack and a lower risk of dying from a heart attack.⁴ Another meta-analysis found each additional 7 grams of fiber reduced the risk of heart disease by 9%.⁵

In addition to this, healthy gut bacteria digest soluble fiber to produce short-chain fatty acids (SCFAs).  SCFAs are absorbed into our blood and signal to the liver to reduce the production of cholesterol and signal to other cells to take up more cholesterol from the blood resulting in lower total cholesterol levels.⁶ So by helping the body to get rid of excess cholesterol, as well as reducing our own production of it, fiber plays a critical role in keeping cholesterol at a healthy level.

Gut Health

Fiber is not only essential for keeping you “regular,” but it also works to keep the cells that line your digestive tract healthy. Since fiber is bulky and helps to keep contents moving smoothly through your system, this reduces any contact that your cells would have with potential toxins. In addition, fiber acts as fuel for our healthy gut bacteria, promoting the growth of health-promoting bacteria, as well as diversity.^7,8 Having well-fed, well-balanced gut bacteria is a crucial part of being healthy.

The SCFAs that the gut bacteria produce have many benefits beyond maintaining healthy cholesterol levels, including strengthening the intestinal lining, helping with mineral absorption, balancing blood sugar, increasing feelings of fullness, contributing to weight loss, reducing inflammation, and influencing gene expression.^9-11

Diabetes

Eating a high-fiber diet can reduce diabetes risk. Research published in Diabetologia found that those who ate the most fiber (above 26 grams per day) had an 18% reduced risk of diabetes compared with those who ate the least.¹² Because high-fiber foods fill you up with fewer calories, promote a feeling of fullness, and reduce the number of calories absorbed from the gut, those who eat high-fiber foods tend to have lower body weights, which further reduces diabetes risk.^13-15 In addition, fiber slows down the digestion of sugar, leading to a slow release of sugar into the bloodstream, which helps with balancing blood glucose levels.

Cancer

Fiber helps to fight certain types of cancer. For hormonal cancers such as breast and prostate cancer, eating a high-fiber diet is beneficial because fiber can remove excess hormones from the body, just as it removes cholesterol.^16,17 Estrogen, for example, can be removed through the digestive tract if a person is eating sufficient fiber in their diet, reducing risk for breast and prostate cancers. Fiber also comes packaged together with other beneficial antioxidants and nutrients, which may contribute to the reduced risk of such cancers.

When it comes to digestive cancers, eating plenty of fiber helps to make sure that carcinogens don’t get the chance to interact with cells lining our digestive system by keeping our digestion moving along swiftly. Fiber can even help those who have already been diagnosed with cancer. In a study of more than 1,500 participants diagnosed with colorectal cancer, every 5 grams of fiber added to their diets reduced the risk of dying by 25% over an eight-year period.¹⁸ The benefit comes not only from improved digestion but also from better insulin sensitivity, reduced inflammation, and healthier gut flora.

The Quick Fiber Check is a handy little tool. Using its simple scoring concept, which takes only a minute or two to learn, you’ll automatically be able to estimate the fiber content of virtually everything in the grocery store.