This was not easy trying how to figure out how to post this article . It is is two parts.
1. Fairly comparing wet and dry foods
Pet owners today have a wide variety of commercially prepared foods to choose from. Unfortunately,
over the years canned food has fallen out of favor and gained a rather negative
reputation — for no good reason at all.
Before we examine various claims about the advantages and disadvantages of dry and wet
food, I’d like to explain how to correctly and fairly compare the nutritional value of different
types of foods:
Since percentages always express a relative content, we have to eliminate the weight of the
moisture by looking at the “solid part” only. This is accomplished by converting all percentages
to “dry matter basis” and mathematically removing the moisture.
As an example, we will look at a dry food with 10% moisture and a wet food with 78% moisture
— average values for common products. If you know how much moisture a food contains,
it is easy to determine the solid parts (the dry matter) by subtracting the moisture percentage
from 100%: 90% and 22% respectively. To determine the dry matter values for the
various components like protein, fat, fiber etc., we divide the given percentage by the amount
of dry matter and multiply the result with 100. E.g. 24% protein in a food with 90% dry matter
will convert to (24% / 90)*100 = 26.67%, 9% protein in a food with 22% dry matter to
(9% / 22) *100 = 40.91%.
As you see, while the wet food contains a higher amount of moisture, the solid part has a
better nutrient concentration than the dry food. The main advantage of canned food is that
even standard varieties that include some grains or other sources of starch, veggies, fruit and
so on have a better concentration of protein and fat (the important parts in the diets of carnivorous
animals like dogs and cats) than dry food, which has a high content of carbohydrates.
Here are some actual numbers by weight to further illustrate:
90% dry matter in a food means that in one pound of dry food
• approximately 14.43 ounces is the solid part
• approximately 1.57 ounces is water,
• you would have to dehydrate 17.78 ounces of dry food
to get one pound of dry matter
22% dry matter in a food means that in one pound of wet food
• approximately 3.53 ounces is the solid part
• approximately 12.47 ounces is water
• you would have to dehydrate 72.8 ounces of wet food
to get one pound of dry matter
Expressed in simpler terms, the dry food is just over four times as concentrated as the wet
2. Advantages and Disadvantages of wet and dry foods
After looking at the comparison, you will probably ask “why should I pay money for water in
food when I can add that myself at almost no cost”? The answer is easy: the concentration of
nutrients isn’t the only aspect to take into consideration, in fact in many cases it may even
become a health problem.
Higher intake of moisture
The amount of moisture in canned food is closer to the composition of what a dog or cat
would naturally eat “in the wild” — whole prey. Their digestive process requires moisture on
many different levels, for example protein is processed in the liver and any waste materials
are filtered and excreted by the kidneys. The liver needs water to process protein and as a
medium to carry waste products to the kidneys, where they are filtered out and most of the
water is reabsorbed.
Pets who eat mostly canned food or a home prepared diet automatically take in more moisture
than those eating kibble, so they do not need to compensate as much by drinking and
excrete less concentrated urine. Contrary to what many people think and pet food companies
claim, dogs (and cats even more so) do not instinctively know how much extra water they
have to drink to make up for what is lacking in dry food.
A greater incidence of bladder diseases and stones/crystals in animals eating dry food is one
result. An increasing number of American Veterinary Medical Association members, including
board-certified veterinary nutritionists, are now strongly recommending the feeding of canned
food only instead of dry kibble to cats, but the issue has not been officially addressed in dogs,
since they have a slightly better ability to compensate by drinking from their water bowl.
Less “empty” calories
Overweight pets also benefit from eating canned food, since unlike carbohydrates, water adds
bulk without any extra “empty” calories (dogs and cats have no nutritional requirements for
carbohydrates, but they do for protein and fat), making the pet feel full faster without the addition
of "empty" calories.
It is important not to overfeed though, since canned food contains a comparatively higher
amount of fat, which delivers over twice as many calories per weight unit as protein and carbohydrates.
Where obesity and not just weight maintenance is a concern, you should choose
lower fat varieties of wet food.
More ideal mineral contents and ratios
While nutrient-dense dry foods are certainly more economical and overall less expensive to
feed, a highly concentrated diet is not always desirable. Especially minerals and trace elements
are present in such high amounts in dry foods that pets can ingest 3-4 times and more
the daily recommended allowance, which can become problematic in the long run.
Wet foods do not only have a more natural moisture content, they also do not supply highly
excessive amounts of minerals like calcium, phosphorus or magnesium, and trace elements
like iron, copper or iodine. The body only requires relatively small amounts of these to function
properly and any excess must be filtered out and excreted by the kidneys.
Less processed nutrition
One of the most important advantages of wet food is that it is much less processed and often
made from higher quality ingredients than dry kibble. Wet food requires no cooking prior to the
canning process, since it is cooked in the can to create a bacteria free environment. Food
being less processed means it is also more digestible, the body doesn't need to work as hard
to utilize it.
Unlike during the manufacturing of dry food, moisture does not have to be removed from the
ingredients of canned food, so food ingredients like meat, grains, potatoes/sweet potatoes,
pasta, vegetables and fruits remain fairly unchanged. Many ingredients used to manufacture
dry food have already been processed at least once before they are mixed into kibble "dough"
and cooked yet again (rendered meat meals and animal-based fats, dried vegetables and
Longer shelf life, less additives and preservatives, no flavoring agents
Canned food generally has a shelf life of two years and more without degradation of nutritional
value, compared to dry food, which can lose much of its nutrient content within a year of
the manufacturing date - depending on how it is preserved. The more natural stabilizers are
used, the shorter the shelf life.
A 1997 study by the University of Illinois Department of Food Science and Human Nutrition
found that canned fruits and vegetables for example provide as much dietary fiber and vitamins
as the same corresponding fresh foods, and in some cases, even more. Fresh foods
begin losing vitamins as soon as they are picked, and often travel long ways.
Although small amounts of preservatives may be present in canned food if they were already
added to specific ingredients used for the formulation, it does not need added preservatives
since the canning process sterilizes and preserves the food in an oxygen-free environment.
There is plenty of meat and fat to make the food palatable without flavoring agents, and since
the can is sealed no humectants are needed to keep moisture in, and no mold inhibitors (like
in semi-moist food products) to prevent the food from becoming moldy.
3. Available types of wet foods
here's part two http://www.havaneseforum.com/showthr...ghlight=versus