I have a fat kitty, now what.
When choosing a food for your cat there are three primary nutrients you need to consider. Protein, fat and carbohydrates are the only variables in determining the energy content of your cat’s food. How these variables are mixed and matched will determine how that food is digested and what effect it will have on their metabolism and their long term health.
Your cat is an obligate carnivore and by definition; cats have no nutritional requirement for starch/carbohydrates. In the wild, cats primarily consume small prey animals of every type. Since mice are a main stay for many small carnivores around the world, it may be helpful to use them as a model. Mice of different ages have different nutrient profiles. Old mice are higher in protein and lower in fat. Baby mice before they leave the nest are very high in fat. When it came time for me to select a model for a diet, I chose juvenile mice just as they were leaving the nest to strike out on their own. The reasons seemed pretty straight forward to me. Old mice are old for a good reason; they were able to avoid predators. Baby mice are protected in the nest and seldom become a meal. Juvenile mice on the other hand are abundant, inexperienced at avoiding capture and are most likely to become a meal for any predator.
The body composition of the typical juvenile mouse is 52-56% protein, 22-28% fat and 4-6% starch/glycogen/carbohydrates. As you can see, your cat was only meant to consume a very small amount of starch/carbs. Think of starch/carbs metabolically as a diabetic human would high fructose corn syrup. For your cat, starch digests much faster than protein and yet protein and starch both have the same 3.5 calories per gram.
Because your cat is an obligate carnivore, the rate at which their metabolism operates and adsorbs glucose from the blood stream, is the same rate that digested protein will supply glucose to the blood stream. Because starch digests much faster, it dumps more glucose/energy into their blood stream than they can use to fuel their metabolism at any given time. The excess glucose has to be removed from the blood to prevent harm, so the body produces excess insulin to remove the excess glucose from the blood and then stores it as fat. Now with the blood glucose levels reduced, your cat again becomes hungry and the whole process starts again. Their body fat slowly rises over time and the pancreas continues to do double duty. This unnecessary over use of the pancreas is most likely why we see such an epidemic of diabetes in our cats. Before 1960, diabetes was rare and most cats only ate meat and no carbs.
When we first started research on low starch/carb diets in 2000, we started with 10% carbs. We were unable to control weight gain until we dropped the total starch/carb content below 6%.
Our research showed us that if we wanted to free feed our cats and not have them gain excess weight we had to keep the starch content below 6%. Now if you restrict feed your cats you can feed them anything you want and force them to maintain a specific weight. However you will probably live with a very unhappy cat in your house and find that your cat will not let you sleep through the night.
What roll does fiber play in the diet?
Some companies use high levels of crude fiber in weight control diets, to slow down digestion in the hopes of getting cats to loose weight. Their diets still generally still need to be fed on a restricted basis in order to control weight. Fiber can slow digestion at very high levels, but we found that it also likely irritated the intestinal lining of the digestive tract. In the wild the amount of fiber a cat consumes is quite low. When you add more than is natural for a cat to consume something has to give. I have seed irritation of the digestive tract, which manifested as soft stool mixed with mucus. I prefer lower levels of crude fiber and higher levels of soluble fiber. We find the combination gives us good transit time, good stool quality and maintains a healthy digestive tract.
What role does fat play.
Fat is crucial to the operation of your cats metabolism. It is common belief that high fat will cause excess weight gain. This is true if you throw starch/carbs into the equation in excess of 6% or you have an imbalance between fat and protein. Like everything else in nutrition all nutrients are relative to every other nutrient. In order for your cats metabolism to operate as it should, you need balance.
If I create a high protein low starch low fat diet, I can force an eight pound cat to gain 2 pounds in 3 weeks. If I increase the fat and change nothing else that same cat will loose the extra 2 pounds in eight weeks. It is all about balance and nature has already showed us that balance through the model of the mouse. In my experience, the average carnivore diet should consist, of roughly 2 parts protein to 1 part fat. Generally I like to see ratio of fat a little higher in our zero formulas with less than 1% starch and fat a little lower in our diets with less than 6% starch.
I have a fat kitty in the house what can I do.
I work with problem cats all the time, but my experience is limited to the nutrient profile of diets with less than 6% starch. With this in mind I can clearly state that there is seldom a need to restrict feed any cat. There are exceptions, but I only run into a hand full of cases each year and I deal with thousands of cats. The hard case that requires a restricted feeding regiment can be described as afraid of most things and they were usually found starving before they were rescued. These are tough cases, however, even most of these can be taught to eat correctly when free fed, although it may take six months of had work.
Remember the following advice is for diets with less than 6% starch.
Most cats overeat because of competition. They feel the need to eat the food before the other cat does. In the wild cats are solitary animals and seldom share unless they have kittens. The best way to alleviate this instinct is to have a never ending supply of food available. This means that you need one bowl of food for each cat in the house and no bowl should be allowed to be less than half full and each bowl should be large enough to hold 1-2 cups of food. It is best if the bowls are 8 inches across and about an inch deep, to keep the cat whiskers from brushing the sides of the bowl. It is also very important that the bowls be placed in out of the way places. Rooms that you spend time in, like the kitchen, will only encourage your cat to overeat.
Cats are social, if you go to the kitchen to prepare and eat food, then they will hang out with you and if their food is there, they will mimic your behavior even if they are not hungry. It is also important to make sure that each bowl is placed in separate parts of the house. When a cat is standing at any one bowl they should not be able to see another cat at any of the other bowls. There is usually one dominant cat in every group and by spacing the bowls you prevent him form controlling all the food. You can also rotate food from bowls that empty less frequently to bowls that empty more often. Rotation will maintain food freshness and prevent waste.
How many times has you cat yelled at you and then dragged you to their bowl and it still has food in it. They are telling you they are worried about starving. Your cat cannot reason that you will fill the dish in time before they starve. They have to assume that you got hit by a buss and they need to eat as much as they can before the other cats in the house figure out that you were in an accident. Once your cats are confident that their food supply is secure they will stop over eating. There are some cats that will gain weight on the less than 6% starch diet, but will not gain weight on the less than 1% starch diets. There is no way to know ahead of time but for problem cats the Zero foods are a better choice to start with. Of course every cat and household is different, but some modification of the above recommendations usually works in almost all difficult cases. Normal behavior for a cat eating a carnivore kibble is for the cat to eat small amounts of food 6-8 times a day and not gain excess weight. They are content, behave better and are more social.
This next statement is probably destined for some controversy and a longer discussion for another day, but I will make a bold and true statement. All healthy cats eating a dry kibble, as described above, will remain perfectly hydrated. Every published hydration study done on wet vs. dry diets was done with diets containing more than 6% starch. We have done hundreds of blood and urine panels and no sign of dehydration. Specific gravity is usually 1.020 for cats consuming a diet with less than 1% starch and 1.025 for diets containing less than 6% starch. The added benefit of low specific gravity is virtually no incidence of crystals/stones.
I look forward your thoughts.