The focus of the holidays always seems to center around food in some way or another. When people talk about nutrition, human or pet, the word “rich” is frequently heard. Foods will be referred to as rich in this vitamin, that mineral, or those fats.


Commercial pet food companies promote their diets as rich in this or that. Those who make homemade diets also like to use the word rich about their chosen ingredients. Unfortunately, we tend to use the word “rich” to mean adequate. The implication is that if a food rich in X is in the diet, in whatever amount, it represents a nutritionally adequate amount of X.


But rich is a comparative word, not a quantitative one. Rich only refers to a comparison to something else, generally a food that is deficient or contains miniscule amounts of the identified nutrients.


The concept of rich has also spawned many new pet feeding philosophies. Many dog owners are now regularly fasting their dogs 1-2 days a week. A celebrity vet is encouraging the “hybrid diet,” where dogs are fed a balanced commercial diet 5 days a week and then given any unbalanced combination of table scraps or people food for 2 days. And a popular manufacturer of raw foods advocates an “ancestral diet” that is fed as little as once a week to provide the nutrients he feels are necessary to achieve the right ancestral mix of protein and fats.


These various programs are predicated on the assumption that replacing foods “rich in” will make up for any deficiencies during deprivation or are capable of correcting all deficiencies that were previously present. It is a concept of “biological catch-up” that is a not supported by nutritional science. I will address the concept of biological catch-up in a separate post.


Rich is a Meaningless Word


As mentioned, rich is a comparative term and is meaningless with regards to nutrition.


I have had actual conversations with owners who insisted that the chicken and brown rice diet they were feeding their dog is adequate in calcium because they added kale, a food considered rich in calcium. When I point out that it takes eighteen cups of cooked kale or nineteen cups of chopped raw kale for every 1,000 calories of chicken and rice to provide the daily requirement of calcium, they are mystified.


If they substituted milk in the diet, another touted rich source of calcium, it would take almost 5 cups of milk and 12 cups of cottage cheese per 1,000 calories of chicken and rice for adequate calcium. It would be impossible and not even advisable to feed these amounts of kale, milk, or cottage cheese to your dog.


The point is, the word rich is meaningless. In science, if it isn’t measured it didn’t happen. If you don’t know the quantity and comparison of that quantity to daily requirements, you cannot assume it is adequate. Rich is not a guarantee of quantity.


I could repeat this exercise for almost every necessary nutrient, even mixing the ingredient choices to reduce volumes, and the results would be the same. It takes an un-consumable amount of food or a consumable amount that far exceeds caloric intake to balance a diet with foods that are “rich in...”


With all due respect to Dr. Oz, “rich in” means nothing.


Dr. Ken Tudor


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