The rate of energy supply of Dietary fibre is

Correct option is C

The correct answer is (c) Dietary fiber, also known as roughage or bulk, is a type of carbohydrate found in plant-based foods such as fruits, vegetables, whole grains, legumes, nuts, and seeds. Unlike other carbohydrates, dietary fiber cannot be fully digested and absorbed by the human digestive system. Instead, it passes through the digestive tract relatively intact, adding bulk to stool and aiding in the process of digestion and elimination.The rate of energy supply, or caloric value, of dietary fiber is often expressed in terms of kilocalories per gram (KCal/g), which represents the amount of energy that can be obtained from the digestion and metabolism of one gram of fiber. While carbohydrates typically provide around 4 KCal/g of energy when fully digested and metabolized, the caloric value of dietary fiber is lower due to its unique properties and limited digestibility.

There are several factors that contribute to the lower caloric value of dietary fiber:

Indigestibility: Dietary fiber consists of complex carbohydrates, primarily cellulose, hemicellulose, and pectin, which are resistant to digestion by human digestive enzymes. Instead of being broken down into simple sugars like other carbohydrates, fiber remains largely intact as it passes through the digestive tract. This indigestibility means that dietary fiber contributes fewer calories to the diet compared to digestible carbohydrates.

Fermentation: Although dietary fiber is not fully digested in the human digestive system, it undergoes partial fermentation by the beneficial bacteria in the colon, known as the gut microbiota. During fermentation, bacteria break down certain components of dietary fiber, such as soluble fibers and resistant starches, into short-chain fatty acids (SCFAs) and gases. While SCFAs can provide some energy to the body, the overall caloric contribution of fiber fermentation is relatively small compared to the digestion of other carbohydrates.

Bulking effect: Dietary fiber has a bulking effect in the digestive tract, increasing the volume and weight of stool and promoting regular bowel movements. This bulking effect helps to promote feelings of fullness and satiety, which can aid in weight management and control appetite. the additional weight and volume contributed by fiber do not represent additional calories consumed by the body.

The caloric value of dietary fiber is commonly estimated to be around 2 KCal/g, although this value may vary depending on the type and source of fiber. Soluble fibers, such as pectins and gums, tend to have a slightly higher caloric value than insoluble fibers, such as cellulose and lignin, due to their greater fermentability and potential to produce SCFAs during fermentation.