The Skinny on Fiber and Weight Management

Fiber is an essential part of our diet. It helps lower cholesterol, enhances digestive health, promotes bowel regularity and improves mineral absorption. In addition, certain kinds of fiber can help keep the pounds off.

Epidemiological as well as clinical trials indicate that fiber plays an important role in weight management. Epidemiological studies show that fiber intake is inversely associated with body weight and body fat (Nutrition, 2005; 21:411-418), and clinical trials indicate that both insoluble and soluble fiber, when added to a person’s diet while keeping energy intake constant, increase post-meal satiety and decrease subsequent hunger. Mean values for published studies show that increasing fiber intake an additional 14 grams per day for more than 2 days leads to a 10% decrease in energy intake and average weight loss of 1.9 kg over 3.8 months. Overweight and obese individuals may experience greater satiety and weight loss from the added fiber in comparison to lean individuals (Nutrition Reviews, 2009; 59(5):129-139).

While both insoluble and soluble fiber are beneficial for weight loss, they work differently within the body. “Insoluble fiber contains no calories and also provides physical bulk to the diet," says Jit Ang, senior vice president, research and development, International Fiber Corporation, North Tonawanda, NY. “Foods containing high levels of insoluble fiber tend to also provide more satisfaction from chewing, plus the feeling of satiety upon ingestion. All of these factors can help reduce the amount of calories consumed."

While insoluble fiber provides bulk, soluble fiber forms a gel when mixed with liquid, which slows the movement of food through the intestines, thereby keeping a person full for a longer period of time. According to Ang, “this may also slow down the absorption of other nutrients, facilitating body cells to burn more sugar for energy, rather than storing fat. By regulating insulin levels—a vital function for diabetics and those with insulin resistance—hunger is controlled, and one will eat less as a result."

Naturally occurring fiber

Fiber is a unique natural component of many foods, notably produce and whole grains. However, studies examining whole-grain sources of fiber and weight control are inconsistent, partly due to variations in study design and because many studies do not account for initial pre-study fiber intake among participants.