Q. Is this a list of foods that are recommended for cats? A. No, it's a reference list of the nutrient content of some
commercial foods. No recommendation is implied by the inclusion
of a food on the tables.
Q. How do you calculate the numbers on the table?
A. The numbers on the table are expressed as "percent of calories"
(protein, fat, carbohydrate) or "amount per 100 calories" (fiber,
phosphorus), based on as-fed information provided by the manufacturer.
For pet foods, I follow the usual assumption that
protein and carbohydrate each contain 3.5 calories per gram, and fat
contains 8.5 calories per gram. You can use this Excel spreadsheet to
see how the calculations are done, or read the longer explanation:
"as fed" or "dry weight" values of
protein, fat, carbohydrate, fiber, and phosphorus from manufacturer.
Cross check: if you also have values for water and ash, the values of
protein, fat, carbohydrate, fiber, ash, and water should add up to
100%. None of them should be negative.
2.) Calculate the amount of protein, etc, in 100 grams of food by
dropping the percent sign. (Example: if a food is 9.5% protein,
100 grams of that food will contain 9.5 grams of protein.)
3.) Calculate total calories by multiplying protein by 3.5, fat
by 8.5, and carbohydrate by 3.5, and summing the results.
4.) Calculate percent of calories from protein by dividing 3.5*protein
by total calories. Calculate percent of calories from fat by
dividing 8.5*fat by total calories. Calculate percent of calories
from carbohydrate by dividing 3.5*carbohydrate by total calories.
Cross-check: these numbers should add up to 100%, except for
5.) Calculate grams of fiber per 100 calories by dividing fiber
by total calories and multiplying by 100.
6.) Calculate mg of phosphorus per 100 calories by dividing phosphorus
by total calories and multiplying by 100,000. (The extra 1000 is
to change the units of phosphorus from grams to milligrams.)
Q. Can I get the
carbohydrate content from the numbers
on the label? A. Not in the United States of America. First of all,
it's not listed on the label. Second, you can't calculate it from
the label because manufacturers aren't required to put average values
of protein, fat, etc. on the label. They are only required to put
"guaranteed" minimum and maximum values on the label. Sometimes
these values are close to what's actually in the food, and sometimes
they are quite different. But in any event they are, by design,
If you live in a country which has consumer-friendly laws on what
should be on pet food labels, carbohydrate content may be listed, or
you may be able to calculate it by adding the values of protein, fat,
water, fiber, and ash, and subtracting that sum from 100% to get "as
carbohydrate. But in the USA, you're likely to get grossly
inaccurate values following this method.
Q. Why aren't the numbers on your table the same as what's on
the label? A. Because I chose to express the numbers on a per-calorie
basis, see above, which I believe makes it easier to compare foods to
each other. The values on the label are "wet weight" values --
they express the amount of each nutrient per 100 grams of food.
Q. Can you add XXX food to your tables? A. Sure. Just send
me the as-fed (not
"guaranteed") information, and I'll be happy to update my database.
need the following: As-fed or dry-weight values of protein, fat,
water, fiber, and phosphorus, and number of calories per can of wet
or cup of dry food. I also like to have the numbers for ash and
You may have to contact the manufacturer directly. A
customer-service-oriented manufacturer will have the information on
their website. Some manufacturers mix and match "guaranteed"
values with "as fed" values, which isn't useful
for these calculations.
Q. How many calories a day should my cat eat?
A. Short answer: Enough to maintain him or her at a healthy
weight and activity level over long periods of time. Longer
common wisdom is that a cat should eat 20-30 calories per pound of cat
per day, depending on its activity level, need to gain or lose weight,
personal metabolism. However, some guardians of elderly diabetic
have found that 20 calories per pound will cause their cat to gain
If the diet contains enough protein and essential nutrients, such
cat can do well on 15-20 calories per pound. Note that, according
veterinary manual, "healthy adult cats need ~5 g of
of high biologic value per kg body wt/day." This translates to
calories from protein per pound body weight per day. From the
document, one can infer that AAFCO recommends that at least 7 calories
pound body weight should come from fat.
Q. What should I feed my cat?
A. I'm sorry, I can't advise you on that. It depends on
your cat's health needs, what he/she will eat, and your budget.
The general rule is to feed the most healthful diet that you can
afford and that your cat will eat. If your cat is diabetic and
receiving insulin, it's also important that the food be fairly
consistent from one meal to the next in terms of total calorie content,
as well as protein, fat, carbohydate, and fiber content, because each
of these factors will affect your cat's insulin needs.
Q. Well, then, what did you feed your diabetic cat?
A. I fed Binky a variety of flavors and brands in rotation,
depending on what he would eat, trying to keep carbohydrates below 12%
calories. I also gave him high-protein treats from my dinner
(as well as a bit of raw chopped London Broil as a snack). I also
to give him 400 IU vitamin E at least once a week, mixed in a low-fat
food. But he was not on insulin, and he did not have any
factors such as pancreatitis or chronic renal failure.
Q. Someone told me that any food with less than 10% calories
from carbohydrates is okay for my cat. Is it really that easy?
A. I wish! No, there are other considerations when deciding
what to feed your cat. Just a few examples: Cats who are prone to
get urinary crystals should get a diet with adequate water, preferably
one that leads to a urinary pH of around 6.5 (mildly acidic);
anecdotally, some of these cats do better when they avoid fish.
Cats who have renal insufficiency/ chronic renal failure usually need
to limit their phosphorus intake, and probably should not have a diet
which is very high in protein. Again anecdotally, many cats with
chronic pancreatitis avoid flare-ups if they avoid very high fat diets,
and the type of fat may also make a difference for them. Cats
with heart problems may benefit from a low-sodium diet. Ingredient
quality is also an important issue. And finally, it is crucial
that a diabetic cat should eat. The healthiest food in the world
doesn't do any good to a cat who refuses to eat it!
Q. My cat needs to eat low-phosphorus foods -- how do the
numbers on your table relate to the dry weight value of phosphorus? A. The relationship between "mg phosphorus per 100 calories"
and "% phosphorus by dry weight" is not exact, as it depends on the
caloric content of the food. However, as a general rule, 1% dry
weight is approximately equal to 240 mg per 100 calories, see chart.
Q. Why are there so few foods that are low-fat and
low-carbohydrate? A. Calories come from protein, fat, and carbohydrate; there
are no other sources except alcohol, which is presumably not an option
for your cat. If you cut down on calories from one source, the
two will tend to be higher. Because protein is the most expensive
component, low-carbohydrate diets tend to be rather high in fat.
is not necessarily a problem. Cat metabolism isn't the same as human
metabolism, and a diet which is moderately high in fat will not cause
weight gain if the calorie content is controlled. However, some
cats with pancreatitis, liver trouble, or high levels of lipids in
their blood may need foods which are lower in fat, even if it means a
diet that's higher in carbohydrate.
Q. I've read your posts on the Feline Diabetes Message Board.
Why do you correct people when they refer to a food as having "7
carbs"? A. Because it's inaccurate, and, further, it may inspire
other people to make the same mistake. Plus, there's no meaning to the
term "carb" used in that context. If you see a "7" in the
carbohydrate column, it means that food has 7 percent of calories from
it does not mean it contains 7 grams of carbohydrate. (The foods
the table are expressed in "per 100 calorie" terms so that foods may be
to each other.) If you'd like to calculate the grams of
in a can (or cup) of a particular food, do the following: Multiply the
per can (or cup) by the percent of calories from carbohydrates, and
Q. Can I tell anything about the quality of the food from your
A. Only a little bit. A food with more carbohydrates has
lots of plant content, which is generally considered low quality.
However, you can't tell whether the protein source is plant-based (e.g.
wheat gluten, soy) or animal-based, and if the latter, whether it comes
from muscle meat, organ meat, by-products, condemned meat, or what.
It's a good idea to look at the list of ingredients and do some
research on the
manufacturer before drawing conclusions about food quality.
Q. Is it true that these tables are provided by cat food
A. No. The food tables are strictly a volunteer effort to
help people make food choices, and I am neither funded nor encouraged
by any food company; in fact, some companies are downright
obstructionist when it comes to providing data. However, it is
true that the numbers are based on information provided by the
manufacturers, and therefore have all the limitations of this
information. I cannot guarantee that they are accurate, or are
up-to-date, or apply to any specific batch of food. I have never
Table Q&A copyright 2005, 2006, 2008 by
M. Peerson. This document can be found at Binky's Page (Tripod); no
other location is authorized.