The thing is, urban coyotes don't eat 'just' bread when they dig through the garbage, it is full of left over meat and bones, which will be their primary choice. Bread and starches are mixed in with everything else they eat, including rats, mice, cats and vibrating bug eyed rat dogs. It's this ability to digest our refuse that has helped to strengthen the survival of the coyote in an urban environment. There are plenty of dogs here, both feral and pets that eat leftovers and these leftovers contain a lot of rice, another starch. Read the ingedients on a bag of dry cat or dog food. A major component of it is flour.
$1:
Raw Materials
The primary ingredients in commercial dog food are by-products of meat, poultry, and seafood, feed grains, and soybean. The animal parts used for pet food may include damaged carcass parts, bones, and cheek meat, and organs such as intestines, kidneys, liver, lungs, udders, spleen, and stomach tissue. Cereal grains, such as soybean meal, corn meal, cracked wheat, and barley, are often used to improve the consistency of the product as well as to reduce the cost of raw materials. Liquid ingredients may include water, meat broth, or blood. Salt, preservatives, stabilizers, and gelling agents are often used and gelling agents to allow greater homogeneity during processing and also control the moisture. They include bean and guar gums, cellulose, carrageenan, and other starches and thickeners. Palatability can be enhanced with yeast, protein, fat, fish solubles, sweeteners, or concentrated flavors called "digests." Generally, artificial flavors are not used, though smoke or bacon flavors may be added to some treats. Most manufacturers supplement pet foods with vitamins and minerals, since some may be lost during processing.
Additional ingredients used for dry foods include corn gluten feed, meat and bone meal, animal fats, and oils. For a meat-like texture, dry foods require more amylaceous, or starch ingredients; proteinaceous adhesives, such as collagen, albumens, and casein; and plasticizing agents. Semi-moist pet foods usually require binders, which come from a variety of sources, such as gels, cereal flours, sulfur-containing amino acids, lower aLkyl mercaptans, lower alkyl sulfides and disulfides, salts, and thiamin. Semimoist products may also incorporate soybean flakes, bran flakes, soluble carbohydrates, emulsifiers, stabilizers, and dried skim milk and dried whey.
Antioxidants are often used to retard oxidation and rancidity of fats. These include butylated hydroxy anisole (BHA), butylated hydroxy toluene (BHT), and tocopherol. To prevent mold and bacterial growth, producers use either sucrose, propylene glycol, sorbic acid, or potassium and calcium sorbates.
http://www.dogs.inhand.de/feeding/dogfood.htmlMany of the animals(coyotes, bears, foxes, raccoons etc) that come from the wild and begin eating from garbage dumps will become ill, but over a couple of generations they are able to adapt their digestive systems and produce enzymes capable of handling these new sources of nutrition. The so called 'pit dogs' look ill for more reasons than just extra starch in their lives. What other kinds of contaminants, poisons and toxins have they consumed while rooting through garbage?