I'm super excited to share my research! 
I’m an animal sciences major and last year one of my kitties, Nym, became sick with diabetes. I had already studied a lot on cat nutrition because of Nocturne’s IBD. When Genny, our third cat, got kidney disease the research became even more intense.
I learned how controversial and confusing cat nutrition can be, even among top scientists and nutritionists.
What I concluded is that cats, being hypercarnivores with a short digestive tract and rapid digestion, as well as a liver meant to convert protein to energy, are meant to eat high protein, moderate fat, and low carb diets.
A mouse (with all its water removed) is about 55% protein (domestic) to 60% (wild mice) or even 70% protein (young wild mice). Their fat content is approx. 20% and they are only 2% carbs with the rest being minerals and the like. The hair, cartilage, feathers, or skin of prey as well as what little digestive content they have gives cats their fiber. A mouse is about 70% water, meaning cats can stay hydrated on prey alone, rarely drinking water (they have a low thirst response/instinct).
Studies show feral cats eat about 63% protein and 23% fat with only 2-3% carbs. Nutritional balance comes from not only meat, but organs, skin, hair, blood, and bones.
Cats eat 10-20 small meals per day, so large and infrequent meals may upset their stomach or leave them feeling hungry for much of the day. Frequent small meals help prevent blood sugar spikes and strong insulin responses.
AAFCO suggests a minimum of 26% protein or 30% for growth/reproduction. But this is a minimum, and in science a minimum does not necessarily mean that an animal thrives. Studies have shown that diabetic cats do best with over 40% protein and that elderly cats are slower to lose muscle mass (associated with disease and death) with a high protein diet (again, over 40%). 50%-60% is even better for diabetic cats.
Fat, which has about twice the calories of protein and carbohydrates, is suggested for a minimum of 9% but studies show cats are naturally attracted to 20-24% fat and that diabetic cats do better with moderate levels of fat (up to 50% of their calories from fat, remembering that calories from fat is not the same thing as percent fat).
Canned food tends to be high in protein and water, both necessary to keep cats healthy. They are about 70% water while dry food tends to be 10-12% and freeze-dried foods are around 6%.
Carb-heavy foods are a cheaper source of nutrients. They do provide energy, vitamins, minerals, and protein but with it comes a lot of starch and sugar, and starch is quickly broken down to sugar, causing a rapid insulin response (high glycemic index foods). Cats bodies aren’t meant to deal with blood sugar spikes, and some scientists theorize that high carb foods may lead to issues with obesity, insulin resistance, and diabetes in cats (as can be seen in horses on high grain diets or people who eat too much sugar and starch).
Dry foods, such as kibble, often require a binding agent that is usually starch based. So dry foods are usually 25-50% carbs while canned foods are more within the 0-25% range. Freeze-dried and air-dried foods may be as low as 1% or less but can be over 20% also, depending on how the company manufactured the food.
Grain-free does not mean low carb, as potatoes are practically pure starch and peas are also a high starch ingredient. Potatoes can even be more quickly absorbed then sugar, causing a worse spike in blood sugar and insulin! Tapioca, cassava, pea starch, potato starch, and similar ingredients are all high glyemic index foods.
Blood sugar spikes from infrequent, large meals of starch/sugar-rich foods may be one of the reasons that Nym got diabetes. He died from the disease within a few months despite a diet change, regular blood testing, vet visits, and daily insulin. It was very hard. We put thousands of dollars and dozens of hours of care into him only to lose him.
So how do we pick a good cat food? I started thinking about this and decided to do a food trial study where I took low carbohydrate and high protein dry foods to find which one cats liked best. The original reason was to help Nym have something to eat overnight so he wouldn’t keep waking up my parents. But it grew into a bigger study, since most of the foods were too high in carbs for a diabetic cat (ideally they should be below 5% and most dry foods are at least 15%).
Many of the cheaper cat foods are 9-11% fat, 30% or more carb, and sometimes below 30% in protein! Studies suggest that wet food is best for cats, since it helps keep them feeling full, hydrated, and can help prevent urinary crystals, concentrated urine, and kidney strain from dehydration. It also is palatable to most cats. However, if you are gone for 8 hours per day at work or if your cat likes to graze through the night, supplementing with dry food can help, since it lasts longer when left out. It also is generally more inexpensive and can be used while traveling and as treats for a reward and for training.
Confusion can occur when comparing foods because the percent changes based on how much water is included. The best way is to compare on a dry-matter basis (with all the water removed) so that kibble can be compared to canned food. Even then cats don’t need percents as much as they need a specific weight in food daily, so calculate the amount eaten daily and then multiply that by the percent in each nutrient to figure out the weight of each nutrient eaten daily. Diabetic studies often use percent from calories (which changes the fat percent a lot due to its higher caloric density). Ratios, especially with minerals, can be important too (such as 1.2 to 1 ratio of calcium to phosphorus).
- Dry Matter Calculator
- Guarantee Converter
Guaranteed analysis is the most common way that nutrients are presented on food packages, but they only show minimums and maximums, not averages. They also aren't on a dry-matter basis and generally don't tell you the ash (minerals/inorganic matter) or carbohydrates. Try finding somewhere online that states the average, not the minimum or maximum. The bags are also only required to tell you the protein, fiber, fat, and moisture, which is a very incomplete picture.
- Ash is just what is left when all the organic matter is burned away, leaving behind the minerals (inorganic material).
Ingredients and their sources can be important too because some foods absorb quicker than others (white potatoes spike blood sugar much worse than sweet potatoes) or may have contaminants like heavy metals (fish often have toxins that built up over time in their flesh, such as mercury). Ratios matter since, for example, zinc reduces the amount of copper that is absorbed but both are necessary nutrients. Digestibility and availability matter also. Studies in mink (a carnivore also) show that egg protein is 90% digestible but feather meal is only 18% digestible and plant proteins are often in the middle, such as corn germ meal only being 57% digestible in mink. High ash may reduce digestibility also and even the genetics of your cat can affect digestibility.
Also, animal-based protein tends to have a better amino acid profile (more taurine, arginine, etc) and helps to make the urine have a healthier pH (grains can cause alkaline urine that can lead to bladder stones, etc). Complete proteins, such as egg protein, have all the amino acids a cat needs in the right amount.
I didn’t really pay attention to sodium, phosphorus, potassium, or magnesium in my trial study, but these can be important to kidney and bladder health. High magnesium is associated with potential bladder stones, phosphorus and sodium are important to kidney health, and potassium may need supplemented in cats with kidney disease. Also, some of the foods I trialed were very high in fat instead of protein. This is because proteins are the most expensive ingredients in animal feeds, so to make them more affordable many companies try to reduce protein to a minimum and instead include higher fat or carb percents to meet the calorie needs of animals.
Kitten foods often are okay for adult cats as far as the protein and fat amounts, but they might have higher mineral content to promote growth, which isn’t always ideal for adult or senior cats. So I stayed away from kitten-specific foods but "all-life stages" were okay.
Calories are also important to consider. If you feed less food so that there are less calories (to promote weight loss) the cat may not get enough of the vitamins and minerals they need daily (by weight). If you want a cat to lose weight you want a relatively low calorie food that is otherwise dense in the other important nutrients. Some studies suggest cats will be satisfied with less food as long as it is high in protein, while others suggest cats get a feeling of fullness from higher fiber diets. Studies with diabetic cats show that high protein helps stabilize blood sugar better than high fiber and promotes weight loss, even with moderate fat.
Mice have 30-35 calories and cats eat ten to twenty per day. An inactive cat may not need that many calories, but its important not to reduce their calories too much. A cat can’t be starved or their liver may become diseased trying to burn fat (fatty liver disease) which is very dangerous and often lethal. To help a cat lose weight they should get about 70% of their maintenance calories and still have multiple small meals daily. I didn't focus on this in my trial either, but my trial did include a number of obese cats.
Protein percent is very debatable for CKD (kidney disease) cats. Some suggest lowering the protein, but lowering the protein can affect other things such as healthy muscle mass (research cachexia or sarcopenia also called "skinny old cat syndrome"), immune system function, and mobility. I’ve chosen to feed our CKD cat a high protein diet, and she is so far doing very well on it. She has a thick hair-coat and hasn’t been losing weight so far. More research is needed in this area to fully understand if reducing protein or just controlling phosphorus, sodium, and potassium is necessary. Cats often lose the ability to absorb and utilize protein and fat as they age, so increasing protein and fat rather than decreasing it seems optimal. Although 1.5 g protein/kg body weight is required for nitrogen balance in adult cats, 5.2 g/kg is recommended to maintain lean body mass. In fact, geriatric cats may need up to 8.5 g/kg/day of protein rather then the minimum set by scientists of 3.5 to 5 g/kg body weight daily. In the webinar "Skinny Old Cats" it says "older cats we think now need more [protein]. 22% of cats over fourteen years of age had decreased protein digestibility. 1/3 of cats had a decrease fat digestibility".
High protein foods seem to help diabetic cats, not just low carb diets, so the protein itself might regulatory for blood sugar, insulin, and insulin responses. Moderate fat (including healthy omega-3, DHA, EPA, and ARA) is suggested, since cats seem to lose weight well on a high protein and low carb diet. It is debatable whether high fiber helps or not. Many people suggest wet food helps diabetic cats more than dry food, even with the same nutrient percentages on a dry matter basis. Normal dry cat foods have about 2-4% fiber while high fiber foods can have 10% or more. Fiber can reduce digestibility, which is something to consider.
Some weight loss diets are high in carbs and protein but low in fat, since fat has more calories per gram. But others suggest high protein and moderate fat with low carbs, since high carbs may lead to abnormal fat deposition (as seen in horses with insulin and blood sugar imbalances), is the way to go for weight loss as well. It may also help the cats feel more satisfied, since they are attracted to protein content in food.
Studies have shown that cats need more protein then dogs to remain healthy. They can use protein to make glucose, so technically they don’t need any carbs in the diet to maintain their blood sugar. They have requirements for amino acids that most animals can produce on their own (arginine, taurine, methionine, and cystine for example). They also don't have the same enzymes and pathways that omnivores have for plant digestion. This isn't to say they can't utilize plants, especially if the ingredients are ground and cooked - potatoes, peas, and grains can be highly digestible - but again, they may not have the proper amino acids and are usually very high in starch.
Cats eat for protein (my teacher said this is opposed to dogs, which eat for volume and fat). One study that allowed cats to control the percents of major nutrients showed they selected about 52% protein, 36% fat, and 12% carbs. Other studies suggest cats eat for carbs, but many of these studies struggled to truly control carb content since many extruded foods require a carb amount.
To prevent too much bias I'll list an article that disagrees with me: Dogs prefer to eat fat, and cats surprisingly tend toward carbs
When looking at carbohydrates there is a difference between fiber (which isn't turned straight to glucose by the body) and starch and sugar (called NFE or NSC, meaning non-structural carbohydrates or carbs other than fiber). Most foods will tell you fiber on the label but many won't tell you carbohydrates, even on their website. They can be calculated if you know ash, protein, fat, fiber, and moisture.
NSC is important in nutrition: When starch/sugar is too high in horses they are prone to obesity, lamninitis (a leading cause of death), and insulin resistance that leads to abnormal fat deposits and chronic inflammation. Also, high dietary NSC is thought to be a cause for the high level of insulinomas (beta cell cancer) in ferrets, which is a leading cause of death for them in the United States. Zoos found that high sugar/starch diets were associated (in multiple species) with GI upset, behavior issues (aggression and self-harming behavior), and obesity.
With all that being said, I chose to study foods above 38% protein as-fed, including extruded kibbles, baked kibbles, air-dried, freeze-dried, and cold-pressed. Unfortunately I couldn't find any cold-pressed foods in the United States, but there are some good options in Europe. Then I asked my clients (I pet-sit) if I could do taste-test trials with their cats. I work with over 40 cats so I got a chance to try with cats of various backgrounds, ages, and health statuses including up to 20 years old! All foods were offered along with their regular food, so they didn't HAVE to eat them. I plan to post the results in a separate thread since this one is so long and complex as it is. I just love nutrition research though!!! : )
Let me know your thoughts and any good articles or sources!
Some Sources I Used:
www.rodentpro.com
www.vin.com
Ferret Diets
www.merckvetmanual.com
Skinny Old Cats
Factors influencing the food preference of cats
link.springer.com
Comparison of voluntary food intake and palatability of commercial weight loss diets in healthy dogs and cats
Protein Intake during Weight Loss Influences the Energy Required for Weight Loss and Maintenance in Cats
Encyclopedia of Feline Clinical Nutrition
researchoutreach.org
Impact of dietary protein on cat health and wellbeing
Do Cats Need High-Protein Cat Food?
Effect of total dietary fiber on satiety in cats.
www.hillspet.com
Satiety's Important Role in Your Cat's Overall Weight and Health
Nutrition of Aging Cats
Dottie Laflamme, DVM, PhDa,*,
Danièlle Gunn-Moore, BVM&S, PhD, MRCVSb
Macronutrients in Feline Health
Cecilia Villaverde, BVSc, PhDa,*, Andrea J. Fascetti,
EMS
www.safergrass.org
Equine Cushing’s Disease – MyHorseUniversity
Understanding Laminitis – World Horse Welfare
Equine Metabolic Syndrome – MyHorseUniversity
Kidney Disease in cats -
Diabetic Cat -
www.ncbi.nlm.nih.gov
Pancreatitis
Cats and Carbohydrates - What is the impact?
Feline obesity -
Feline Lower Urinary Tract Disorders -
Webinar: Laminitis Lessons with Don Walsh, DVM
equisearch
Nutritional Management of Chronic Renal Disease in Dogs and Cats
Denise A. Elliott, BVSc, PhD
Royal Canin USA, 500 Fountain Lakes Boulevard, Suite 100, St. Charles, MO, 63301, USA
Understanding and Managing Obesity in Dogs and Cats
Dottie P. Laflamme, DVM, PhD
Nestle Purina Pet Care Research, Checkerboard Square-Research South,
St. Louis, MO 63164, USA
Nutrition and Lower Urinary Tract Disease in Cats
Joseph W. Bartges, DVM, PhD*, Claudia A. Kirk, DVM, PhD
Department of Small Animal Clinical Sciences, Veterinary Teaching Hospital,
College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996–4544, USA
Nutrition and Immune Function
Korinn E. Saker, MS, DVM, PhD
Department of Large Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary
Medicine, Blacksburg
Feline Diabetes Mellitus: Low Carbohydrates Versus High Fiber?
Claudia A. Kirk, DVM, PhDa
Department of Small Animal Clinical Sciences, Veterinary Teaching Hospital,
College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996-4545, USA
Nutritional Management for Dogs and Cats with Chronic Kidney Disease
Valerie J. Parker, DVM
Canine and Feline Obesity Management
Megan Shepherd, DVM, PhD
Senior Pet Nutrition and Management
Julie A. Churchill, DVM, PhDa,*, Laura Eirmann, DVMb,c
Nutritional Management for Dogs and Cats with Chronic Kidney Disease
Valerie J. Parker, DVM
Nutritional Concerns for Cancer, Cachexia, Frailty, and Sarcopenia in Canine and Feline Pets
Korinn E. Saker, MS, DVM, PhD
Understanding the Nutritional Needs of Healthy Cats and Those with Diet-Sensitive Conditions
Dottie P. Laflamme, DVM, PhD
Assessing Nutritional Requirements and Current Intake
Angela Witzel-Rollins, DVM, PhD*, Maryanne Murphy, DVM, PhD
The importance of a high protein diet in managing feline diabetics
www.dvm360.com
Feline diabetes mellitus (Proceedings)
Food Intake and Blood Glucose in Normal and Diabetic Cats Fed Ad Libitum
The Role of Diet in the Prevention and Management of Feline Diabetes
Cats and Carbohydrates: Implications for Health and Disease PDF
Dottie P. Laflamme, DVM, PhD, DACVN
The Role of Diet in the Prevention and Management of Feline Diabetes
Insulin sensitivity, fat distribution, and adipocytokine response to different diets in lean and obese cats before and after weight loss
catcentric.org
Cats, Carbs and Calories: An Obligate Carnivore’s Perspective
Advances in Dietary Management of Obesity in Dogs and Cats
Effect of acarbose on postprandial blood glucose concentrations in healthy cats fed low and high carbohydrate diets
Dietary carbohydrate source affects glucose concentrations, insulin secretion, and food intake in overweight cats
Therapies for Feline Chronic Kidney Disease: What is the Evidence?
Nutritional Modulation of Insulin Resistance in the True Carnivorous Cat: A Review
PROTEINURIA
Harriet M. Syme and Jonathan Elliott
Journal Article
Starch characterization of commercial extruded dry pet foods
Isabella Corsato Alvarenga, Charles G Aldrich
The Diabetic Cat: more than just insulin injections
www.feline-friends.org.uk
PDF
Increased Dietary Protein Promotes Fat Loss and Reduces Loss of Lean Body Mass During Weight Loss in Cats
Dorothy P. Laflamme, DVM, PhD Steven S. Hannah, PhD
EAZA - Beyond Enrichment - modern zoo animal feeding
PDF
The carnivore connection to nutrition in cats
Debra L. Zoran, DVM, PhD, DACVIM
The macronutrient content of prey: analysis and effect on satiety in cats
petkeen.com
Can Dry Food Cause Diabetes in Cats? Everything You Need to Know!
Emma Stenhouse
catinfo.org
Feline Diabetes
Lisa A. Pierson, DVM
PDF
Introduction to Feeding Normal Cats
P. Jane Armstrong Kathy L. Gross Iveta Becvarova Jacques Debraekeleer
EAZA Animal Welfare Webinar – Amy Plowman – Diet and welfare: a focus on the right carbohydrates
springnaturals.com
What is the Glycemic Index, and Why It's Important for Your Cat and Dog's Diet
www.ibdkitties.net
Diabetes
Nutritional Management of Chronic Renal Disease in Dogs and Cats
Denise A. Elliott, BVSc, PhD
littlebigcat.com
10 Reasons Why Dry Food Is Bad for Cats & Dogs
vetnutrition.tufts.edu
Cats are not Small Dogs: Unique Nutritional Needs of Cats
Nutritional Management of Cats and Dogs with Diabetes Mellitus
Valerie J. Parker, DVMa, Richard C. Hill, MA, VetMB, PhD, MRCVSb,*
Carnivores, Omnivores & Herbivores - Dr. Bills Pet Nutrition
www.ncbi.nlm.nih.gov
Cats and Carbohydrates: The Carnivore Fantasy?
www.merckvetmanual.com
Nutrition in Zoo Carnivores
By Joeke Nijboer
I’m an animal sciences major and last year one of my kitties, Nym, became sick with diabetes. I had already studied a lot on cat nutrition because of Nocturne’s IBD. When Genny, our third cat, got kidney disease the research became even more intense.
I learned how controversial and confusing cat nutrition can be, even among top scientists and nutritionists.
What I concluded is that cats, being hypercarnivores with a short digestive tract and rapid digestion, as well as a liver meant to convert protein to energy, are meant to eat high protein, moderate fat, and low carb diets.
A mouse (with all its water removed) is about 55% protein (domestic) to 60% (wild mice) or even 70% protein (young wild mice). Their fat content is approx. 20% and they are only 2% carbs with the rest being minerals and the like. The hair, cartilage, feathers, or skin of prey as well as what little digestive content they have gives cats their fiber. A mouse is about 70% water, meaning cats can stay hydrated on prey alone, rarely drinking water (they have a low thirst response/instinct).
Studies show feral cats eat about 63% protein and 23% fat with only 2-3% carbs. Nutritional balance comes from not only meat, but organs, skin, hair, blood, and bones.
Cats eat 10-20 small meals per day, so large and infrequent meals may upset their stomach or leave them feeling hungry for much of the day. Frequent small meals help prevent blood sugar spikes and strong insulin responses.
AAFCO suggests a minimum of 26% protein or 30% for growth/reproduction. But this is a minimum, and in science a minimum does not necessarily mean that an animal thrives. Studies have shown that diabetic cats do best with over 40% protein and that elderly cats are slower to lose muscle mass (associated with disease and death) with a high protein diet (again, over 40%). 50%-60% is even better for diabetic cats.
Fat, which has about twice the calories of protein and carbohydrates, is suggested for a minimum of 9% but studies show cats are naturally attracted to 20-24% fat and that diabetic cats do better with moderate levels of fat (up to 50% of their calories from fat, remembering that calories from fat is not the same thing as percent fat).
Canned food tends to be high in protein and water, both necessary to keep cats healthy. They are about 70% water while dry food tends to be 10-12% and freeze-dried foods are around 6%.
Carb-heavy foods are a cheaper source of nutrients. They do provide energy, vitamins, minerals, and protein but with it comes a lot of starch and sugar, and starch is quickly broken down to sugar, causing a rapid insulin response (high glycemic index foods). Cats bodies aren’t meant to deal with blood sugar spikes, and some scientists theorize that high carb foods may lead to issues with obesity, insulin resistance, and diabetes in cats (as can be seen in horses on high grain diets or people who eat too much sugar and starch).
Dry foods, such as kibble, often require a binding agent that is usually starch based. So dry foods are usually 25-50% carbs while canned foods are more within the 0-25% range. Freeze-dried and air-dried foods may be as low as 1% or less but can be over 20% also, depending on how the company manufactured the food.
Grain-free does not mean low carb, as potatoes are practically pure starch and peas are also a high starch ingredient. Potatoes can even be more quickly absorbed then sugar, causing a worse spike in blood sugar and insulin! Tapioca, cassava, pea starch, potato starch, and similar ingredients are all high glyemic index foods.
Blood sugar spikes from infrequent, large meals of starch/sugar-rich foods may be one of the reasons that Nym got diabetes. He died from the disease within a few months despite a diet change, regular blood testing, vet visits, and daily insulin. It was very hard. We put thousands of dollars and dozens of hours of care into him only to lose him.
So how do we pick a good cat food? I started thinking about this and decided to do a food trial study where I took low carbohydrate and high protein dry foods to find which one cats liked best. The original reason was to help Nym have something to eat overnight so he wouldn’t keep waking up my parents. But it grew into a bigger study, since most of the foods were too high in carbs for a diabetic cat (ideally they should be below 5% and most dry foods are at least 15%).
Many of the cheaper cat foods are 9-11% fat, 30% or more carb, and sometimes below 30% in protein! Studies suggest that wet food is best for cats, since it helps keep them feeling full, hydrated, and can help prevent urinary crystals, concentrated urine, and kidney strain from dehydration. It also is palatable to most cats. However, if you are gone for 8 hours per day at work or if your cat likes to graze through the night, supplementing with dry food can help, since it lasts longer when left out. It also is generally more inexpensive and can be used while traveling and as treats for a reward and for training.
Confusion can occur when comparing foods because the percent changes based on how much water is included. The best way is to compare on a dry-matter basis (with all the water removed) so that kibble can be compared to canned food. Even then cats don’t need percents as much as they need a specific weight in food daily, so calculate the amount eaten daily and then multiply that by the percent in each nutrient to figure out the weight of each nutrient eaten daily. Diabetic studies often use percent from calories (which changes the fat percent a lot due to its higher caloric density). Ratios, especially with minerals, can be important too (such as 1.2 to 1 ratio of calcium to phosphorus).
- Dry Matter Calculator
- Guarantee Converter
Guaranteed analysis is the most common way that nutrients are presented on food packages, but they only show minimums and maximums, not averages. They also aren't on a dry-matter basis and generally don't tell you the ash (minerals/inorganic matter) or carbohydrates. Try finding somewhere online that states the average, not the minimum or maximum. The bags are also only required to tell you the protein, fiber, fat, and moisture, which is a very incomplete picture.
- Ash is just what is left when all the organic matter is burned away, leaving behind the minerals (inorganic material).
Ingredients and their sources can be important too because some foods absorb quicker than others (white potatoes spike blood sugar much worse than sweet potatoes) or may have contaminants like heavy metals (fish often have toxins that built up over time in their flesh, such as mercury). Ratios matter since, for example, zinc reduces the amount of copper that is absorbed but both are necessary nutrients. Digestibility and availability matter also. Studies in mink (a carnivore also) show that egg protein is 90% digestible but feather meal is only 18% digestible and plant proteins are often in the middle, such as corn germ meal only being 57% digestible in mink. High ash may reduce digestibility also and even the genetics of your cat can affect digestibility.
Also, animal-based protein tends to have a better amino acid profile (more taurine, arginine, etc) and helps to make the urine have a healthier pH (grains can cause alkaline urine that can lead to bladder stones, etc). Complete proteins, such as egg protein, have all the amino acids a cat needs in the right amount.
I didn’t really pay attention to sodium, phosphorus, potassium, or magnesium in my trial study, but these can be important to kidney and bladder health. High magnesium is associated with potential bladder stones, phosphorus and sodium are important to kidney health, and potassium may need supplemented in cats with kidney disease. Also, some of the foods I trialed were very high in fat instead of protein. This is because proteins are the most expensive ingredients in animal feeds, so to make them more affordable many companies try to reduce protein to a minimum and instead include higher fat or carb percents to meet the calorie needs of animals.
Kitten foods often are okay for adult cats as far as the protein and fat amounts, but they might have higher mineral content to promote growth, which isn’t always ideal for adult or senior cats. So I stayed away from kitten-specific foods but "all-life stages" were okay.
Calories are also important to consider. If you feed less food so that there are less calories (to promote weight loss) the cat may not get enough of the vitamins and minerals they need daily (by weight). If you want a cat to lose weight you want a relatively low calorie food that is otherwise dense in the other important nutrients. Some studies suggest cats will be satisfied with less food as long as it is high in protein, while others suggest cats get a feeling of fullness from higher fiber diets. Studies with diabetic cats show that high protein helps stabilize blood sugar better than high fiber and promotes weight loss, even with moderate fat.
Mice have 30-35 calories and cats eat ten to twenty per day. An inactive cat may not need that many calories, but its important not to reduce their calories too much. A cat can’t be starved or their liver may become diseased trying to burn fat (fatty liver disease) which is very dangerous and often lethal. To help a cat lose weight they should get about 70% of their maintenance calories and still have multiple small meals daily. I didn't focus on this in my trial either, but my trial did include a number of obese cats.
Protein percent is very debatable for CKD (kidney disease) cats. Some suggest lowering the protein, but lowering the protein can affect other things such as healthy muscle mass (research cachexia or sarcopenia also called "skinny old cat syndrome"), immune system function, and mobility. I’ve chosen to feed our CKD cat a high protein diet, and she is so far doing very well on it. She has a thick hair-coat and hasn’t been losing weight so far. More research is needed in this area to fully understand if reducing protein or just controlling phosphorus, sodium, and potassium is necessary. Cats often lose the ability to absorb and utilize protein and fat as they age, so increasing protein and fat rather than decreasing it seems optimal. Although 1.5 g protein/kg body weight is required for nitrogen balance in adult cats, 5.2 g/kg is recommended to maintain lean body mass. In fact, geriatric cats may need up to 8.5 g/kg/day of protein rather then the minimum set by scientists of 3.5 to 5 g/kg body weight daily. In the webinar "Skinny Old Cats" it says "older cats we think now need more [protein]. 22% of cats over fourteen years of age had decreased protein digestibility. 1/3 of cats had a decrease fat digestibility".
High protein foods seem to help diabetic cats, not just low carb diets, so the protein itself might regulatory for blood sugar, insulin, and insulin responses. Moderate fat (including healthy omega-3, DHA, EPA, and ARA) is suggested, since cats seem to lose weight well on a high protein and low carb diet. It is debatable whether high fiber helps or not. Many people suggest wet food helps diabetic cats more than dry food, even with the same nutrient percentages on a dry matter basis. Normal dry cat foods have about 2-4% fiber while high fiber foods can have 10% or more. Fiber can reduce digestibility, which is something to consider.
Some weight loss diets are high in carbs and protein but low in fat, since fat has more calories per gram. But others suggest high protein and moderate fat with low carbs, since high carbs may lead to abnormal fat deposition (as seen in horses with insulin and blood sugar imbalances), is the way to go for weight loss as well. It may also help the cats feel more satisfied, since they are attracted to protein content in food.
Studies have shown that cats need more protein then dogs to remain healthy. They can use protein to make glucose, so technically they don’t need any carbs in the diet to maintain their blood sugar. They have requirements for amino acids that most animals can produce on their own (arginine, taurine, methionine, and cystine for example). They also don't have the same enzymes and pathways that omnivores have for plant digestion. This isn't to say they can't utilize plants, especially if the ingredients are ground and cooked - potatoes, peas, and grains can be highly digestible - but again, they may not have the proper amino acids and are usually very high in starch.
Cats eat for protein (my teacher said this is opposed to dogs, which eat for volume and fat). One study that allowed cats to control the percents of major nutrients showed they selected about 52% protein, 36% fat, and 12% carbs. Other studies suggest cats eat for carbs, but many of these studies struggled to truly control carb content since many extruded foods require a carb amount.
To prevent too much bias I'll list an article that disagrees with me: Dogs prefer to eat fat, and cats surprisingly tend toward carbs
When looking at carbohydrates there is a difference between fiber (which isn't turned straight to glucose by the body) and starch and sugar (called NFE or NSC, meaning non-structural carbohydrates or carbs other than fiber). Most foods will tell you fiber on the label but many won't tell you carbohydrates, even on their website. They can be calculated if you know ash, protein, fat, fiber, and moisture.
NSC is important in nutrition: When starch/sugar is too high in horses they are prone to obesity, lamninitis (a leading cause of death), and insulin resistance that leads to abnormal fat deposits and chronic inflammation. Also, high dietary NSC is thought to be a cause for the high level of insulinomas (beta cell cancer) in ferrets, which is a leading cause of death for them in the United States. Zoos found that high sugar/starch diets were associated (in multiple species) with GI upset, behavior issues (aggression and self-harming behavior), and obesity.
With all that being said, I chose to study foods above 38% protein as-fed, including extruded kibbles, baked kibbles, air-dried, freeze-dried, and cold-pressed. Unfortunately I couldn't find any cold-pressed foods in the United States, but there are some good options in Europe. Then I asked my clients (I pet-sit) if I could do taste-test trials with their cats. I work with over 40 cats so I got a chance to try with cats of various backgrounds, ages, and health statuses including up to 20 years old! All foods were offered along with their regular food, so they didn't HAVE to eat them. I plan to post the results in a separate thread since this one is so long and complex as it is. I just love nutrition research though!!! : )
Let me know your thoughts and any good articles or sources!
Some Sources I Used:
Nutrient Composition of Whole Vertebrate Prey
Discover the nutrition info for whole vertebrate prey online. If you're trying to decide what to feed your pet, let this nutrient composition guide help with your decision. Read about nutrient composition of whole vertebrate prey from Rodent Pro today. Free ground shipping on orders totaling...
Ferret Diets: You are being redirected to updated information on this topic.
A nutritious and balanced diet is the foundation of good health for all creatures including ferrets. Ferrets have been kept in captivity since 300 BC, but it is only in the last 40 years that we have changed their diet from raw foods to commercially processed foods. We have made the change...
www.vin.com
Nutrition in Reptiles - Management and Nutrition - Merck Veterinary Manual
Learn about the veterinary topic of Nutrition in Reptiles. Find specific details on this topic and related topics from the Merck Vet Manual.
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Factors influencing the food preference of cats
Comparison of voluntary food intake and palatability of commercial weight loss diets in healthy dogs and cats - BMC Veterinary Research
Background Obesity in dogs and cats is usually managed by dietary energy restriction using a purpose-formulated weight loss diet, but signs of hunger and begging commonly occur causing poor owner compliance. Altering diet characteristics so as to reduce voluntary food intake (VFI) can improve...
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Protein Intake during Weight Loss Influences the Energy Required for Weight Loss and Maintenance in Cats
Encyclopedia of Feline Clinical Nutrition
Impact of dietary protein on cat health and wellbeing
Dayakar Badri, Matthew Jackson, and Dennis Jewell research the effects of varying dietary protein levels on healthy adult cats.
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Do Cats Need High-Protein Cat Food?
Dr. Kelly Sulik explains the importance of protein in a cat’s diet and whether or not a high-protein diet is best for your cat.
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Pancreatitis was considered a rare disease in the cat until a couple of decades ago when several retrospective studies of severe acute pancreatitis were published. It was apparent that few of the diagnostic tests of value in the dog were helpful in cats. ...
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Dottie P. Laflamme, DVM, PhD
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Nutrition and Lower Urinary Tract Disease in Cats
Joseph W. Bartges, DVM, PhD*, Claudia A. Kirk, DVM, PhD
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College of Veterinary Medicine, The University of Tennessee, Knoxville, TN 37996–4544, USA
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Claudia A. Kirk, DVM, PhDa
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Valerie J. Parker, DVM
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Valerie J. Parker, DVM
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Korinn E. Saker, MS, DVM, PhD
Understanding the Nutritional Needs of Healthy Cats and Those with Diet-Sensitive Conditions
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Diabetes mellitus (DM) can be defined as a group of metabolic diseases characterized by hyperglycemia, which results from defects in insulin secretion, insulin action, or both. DM can occur because of disease affecting the endocrine pancreas and other endocrinopathies such as acromegaly.
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Written by Tracy Dion for Raw Instincts Magazine November 2012 and last updated January 2013. Around the Holidays, we think of the gifts and blessings in our lives with gratitude. One of the most precious gifts many of us share is the affection of a cat (or two or three!). Unfortunately, felin
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PROTEINURIA
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Live webinar date: 28th November 2018 8pm A diagnosis of diabetes can be a daunting prospect for many owners. It is a serious illness, but read more >
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Dorothy P. Laflamme, DVM, PhD Steven S. Hannah, PhD
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As pet owners, we want to ensure that we are feeding our cats the best possible food to promote great health. Find out if dry food has any relation to diabetes in cats with this guide.
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A veterinarian discusses the treatment and prevention of feline diabetes, discusses the detrimental impact of dietary carbohydrates on the blood glucose balance in cats..
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P. Jane Armstrong Kathy L. Gross Iveta Becvarova Jacques Debraekeleer
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What is the Glycemic Index, and Why It's Important for Your Cat and Do
It’s completely understandable if you are wondering what the Glycemic Index is and why learning more about it is important for both you and your pet. Simply stated, the type of food your pet consumes matters! Especially when your goal is to not only provide your beloved fur baby with a...
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IBDKitties – Helping Save Lives…One Paw at a Time
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Nutritional Management of Chronic Renal Disease in Dogs and Cats
Denise A. Elliott, BVSc, PhD
10 Reasons Why Dry Food Is Bad for Cats & Dogs | Little Big Cat - Dr. Jean Hofve
Strictly carnivorous cats preferentially use protein and fat for energy, and these pathways are mandatory. Felines can digest and absorb carbohydrates, but those carbs mostly turn quickly and directly into fat.
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Different from dogs, who are omnivores (meaning they are designed to eat a combination of animal and plant foods), cats are carnivores and have unique metabolism compared to many other domestic animals.
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Nutritional Management of Cats and Dogs with Diabetes Mellitus
Valerie J. Parker, DVMa, Richard C. Hill, MA, VetMB, PhD, MRCVSb,*
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Cats and Carbohydrates: The Carnivore Fantasy?
The domestic cat’s wild ancestors are obligate carnivores that consume prey containing only minimal amounts of carbohydrates. Evolutionary events adapted the cat’s metabolism and physiology to this diet strictly composed of animal tissues ...
Nutrition in Zoo Carnivores - Management and Nutrition - Merck Veterinary Manual
Learn about the veterinary topic of Nutrition in Zoo Carnivores. Find specific details on this topic and related topics from the Merck Vet Manual.
By Joeke Nijboer
