Why Fiber is the Not-So-Secret Key to Weight Loss

By Brooke Zigler, MPP, RDN, LD – December 31, 2018


While many weight loss diets focus on eliminating foods, you may be surprised to learn that the key to weight loss is sometimes about adding more food into your diet. Eating more of certain types of foods, like those high in dietary fiber, can be one way to boost your metabolism, promote satiety and put you on a healthy track to weight loss. 

What is Dietary Fiber?

Fiber, often called roughage or bulk, is a type of carbohydrate that cannot be digested by the human body. It is found only in plant foods such as vegetables, fruits, grains and legumes. Since fiber is the indigestible part of the carbohydrate and our bodies are unable to break it down, it is calorie-free. 

While fiber is an important part of our diets, most Americans do not get enough. The recommended daily intake for women is 25 grams and 38 grams for men. However, the average adult intake of fiber is half of the recommended amount.  

Soluble vs. Insoluble Fiber

There are two types of fiber: soluble and insoluble. They are both beneficial and play important roles in digestion and overall health. 

Soluble fiber is the indigestible food components that dissolve in water to form a gel. This type of fiber helps to lower blood cholesterol, slows glucose absorption and digestion, and also softens stools. It can also lower the risk of heart disease and diabetes. Soluble fiber is found in whole-grain products including barley, oats, oat bran, and rye, and fruits such as apples and citrus, legumes, seeds and vegetables.

Insoluble fiber is the indigestible food components that do not dissolve in water. This type of fiber helps to bulk stools and speed the passage of stools through the digestive tract, which burns calories in the process. It can alleviate constipation, prevent hemorrhoids and diverticulosis, and can also help with weight management. Insoluble fiber is found in brown rice, fruits, legumes, seeds, vegetables such as cabbage, carrots, brussels sprouts, wheat bran and whole grains. 


Fiber and Weight Loss

What makes fiber the not-so-secret key to weight loss?

Since fiber adds bulk to foods and binds to water, it provides a feeling of fullness and satisfaction after a meal. High-fiber foods also take more time and effort to eat since there is more chewing involved. Since it usually takes 20 minutes for the brain to receive the signal that the stomach is full, a person who eats slowly and savors each bite will typically eat less before the satiety signal eventually reaches the brain. 

Furthermore, our bodies cannot actually digest fiber. However, it still attempts to do so, which burns calories during the process, helping to boost your metabolism. Fiber also slows digestion, which provides us with a steady blood glucose level. As a result, you are likely to stay fuller for a longer period of time, meaning you won’t be reaching for a snack so quickly after having a fiber-rich meal. 

When increasing your fiber intake, it is equally important to also ensure sufficient hydration. Water is necessary for fiber to easily pass through the digestive tract, so not having enough may result in constipation. It is also recommended to slowly introduce fiber into the diet to prevent excess bloating or gas. 

Even if you’re not looking to lose weight, the benefits of fiber are far reaching. Fiber is important for overall bowel health, reducing the risk of certain cancers, heart disease and diabetes. It also lowers cholesterol and may help you live a longer life.  



Related Articles