To be digested by cats and dogs, starch must be very well cooked or it will ferment in the large intestine and cause diarrhoea.Too much starch can have the same result if the amount ingested exceeds the animal’s enzymatic digestive capacity (in Nordic dog and cat breeds for instance).
A little background information
Starches are carbohydrate molecules in which thousands of glucose molecules are linked together by simple chemicals bonds.
Its role in the body
Starches are only used to provide energy to the animal, after being degraded by the digestive process to help the intestine gradually absorb the glucose molecules.
Natural sources
Starches are reserve substances (equivalent to fats in animals) peculiar to plants: cereals (rice, maize, wheat, barley, etc), potato or manioc tubers. Starch represents 50-70% of cereal grain. In dry food, cereal starch helps obtain the typical honeycombed structure of the kibbles (expansion).