The role of fiber in weight loss diets

The role of fiber in weight loss diets

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Sep 01, 2011


Beth A. Flickinger, PhD, RD
One of the main reasons that owners have trouble helping their dogs and cats lose weight is the difficulty in long-term compliance.1 Not surprisingly, owners cited begging for food or treats and dogs that eat food intended for other pets as common obstacles in a program to help pets lose weight.

Dietary fiber may help dogs and cats feel fuller by diluting calories. Fiber is essentially calorie-free, so adding fiber to a diet helps reduce the caloric density, which allows the pet to eat a larger volume of food without consuming additional calories. This larger volume of food helps contribute to gastric distension, which is one of the satiety cues that signals to the pet that it is full.

An important consideration for promoting optimal weight loss and overall well-being is the type and amount of fiber in the diet. Commercial weight loss diets for pets vary in their fermentable and nonfermentable fiber content.

Fermentable fiber

In the past, fiber was classified based on its structure as soluble or insoluble, depending on whether or not it could be dissolved in water. A newer approach is to classify fiber based on its functionality as fermentable or nonfermentable, depending on whether or not bacteria can ferment (use) the fiber. In general, soluble fiber is fermentable, and insoluble fiber is not, but since there are several exceptions to the rule, the functional classification is preferred.

Fermentable fiber, as indicated by its name, is naturally fermented by colonic bacteria in dogs and cats. In the fermenting process, nutrients called short-chain fatty acids are produced. These short-chain fatty acids, especially butyrate, are then used by the intestinal cells as an important energy source. Short-chain fatty acids have been shown to support healthy intestinal cell growth and development and to improve nutrient absorption.2 In contrast, nonfermentable fiber is poorly fermented or not fermented at all and, therefore, does not yield short-chain fatty acids and cannot help fuel the intestine.

Fermentable fiber has also been shown to promote satiety in dogs. In one study testing moderate levels of a fermentable-fiber blend of beet pulp and fructooligosac-charides (FOS), this fiber blend produced more of the satiety-signaling hormone glucagon-like peptide-1 than nonfermentable fiber did.3 Furthermore, another study demonstrated that dogs consuming a diet containing a fermentable-fiber blend not only had more of the health-promoting short-chain fatty acids, but also tended to eat less than dogs fed a diet with nonfermentable fiber.4