What Nutritionists Wish You Knew: 5 Homecooked Diet Mistakes & Misconceptions

by Cailin R. Heinze, VMD, MS, DACVIM (Nutrition)

March 31, 2023

in Finding the Best Food for Your Pet, Petfoodology Blog, Trending Topics in Pet Nutrition

A common task of a Board Certified Veterinary Nutritionist^® is to design custom homemade diet recipes for pets that have health issues or for pet owners who prefer not to use commercial foods. We’ve covered some general mistakes that pet owners often make with homecooked diets when they don’t work with a veterinary nutritionist, as well as some situations where cooking for your pet may not be optimal. In this post, I’d like to focus on misconceptions and mistakes about homecooked diets that my colleagues and I frequently run into with our clients – pet owners who get their recipes from a veterinary nutritionist. These issues tend to come up after the consultation, when our clients receive the completed recipe and start cooking. These misconceptions often cause frustration for nutritionist and pet owner alike.

Equating volume of food with calories – after a homemade recipe is created for a pet, it is common to have the pet owner question the volume amount of the food because it looks like less or more than they expected it to be, often based on the pet’s previous diet. There may be the perception that there isn’t enough food, but more frequently, the concern is about too much food. Homemade diets are formulated to provide the amount of calories that the nutritionist feels is appropriate for the pet, either based on the pet’s diet history, or on published equations. Nutritionists are trained to think in terms of calories, not volume, and so the volume of the food rarely comes into consideration during the formulation process unless it seems particularly high. Pet owners, on the other hand, tend to think about food in terms of volume, not calories. Especially for pets that were previously fed dry diets, many owners are surprised by the amount of homemade food that needs to be fed each day. Most commercial dry foods are between 300-400 calories (kcal) per cup. Most home-cooked foods are much lower because of their higher moisture content. This higher moisture results in more cups that need to be fed every day. For example, chicken breast and rice are just over 200 kcal per cup each, so if you go from a dog food that is 400 kcal/cup to a chicken and rice-based homemade diet, you’ll need to feed about twice as much volume. For pets with health problems that require lower fat diets, the volume to feed will be even higher than for pets that are otherwise healthy as fat provides a lot of calories in a very little volume compared to protein or carbohydrates. Using mostly vegetables as carbohydrate sources rather than grains or other starches can also result in large volumes of food because vegetables like green beans, broccoli, zucchini, etc. are quite low in calories per volume. Therefore, grain-free, lower starch, and/or lower fat homemade diets are often higher in volume than expected based on more traditional pet foods!
Expecting more meat – Dog foods for healthy dogs are typically 20-28% of calories from protein while cat foods are typically 28-38% of calories from protein (remember, though, that these percentages are not the same as the ones you see on pet food labels, which are based on percent of weight not percent of calories). For high protein meats, this means that the amount (volume) of protein is often quite less than the amount of carbohydrate in the diet, especially for dog diets. This isn’t obvious in commercial foods but is much more apparent for homecooked diets when you’re measuring out twice as much carbohydrate as protein for a dog. Some of the fat in a diet recipe will come from meat, but fat will usually be added separately as well to meet essential fatty acid requirements. A little fat goes a long way in terms of calories, so the total amounts of fat will generally be small. All of this means that a typical dog recipe that might contain roughly 1/3 each protein, fat, and carbohydrate on a calorie basis is going to *look* like a lot more carbohydrate than protein or fat.If the diet is purposely low in protein or fat or both to address health issues like kidney disease and pancreatitis, then the amount of protein in the recipe, while appropriate for the pet, can look very small to the pet owner, which can result in the pet owner thinking that the nutritionist made a mistake. Therefore, even if the amount of one ingredient isn’t as much as you’d expect, follow the recipe! If your pet is not eating the diet well, talk to the nutritionist who formulated the diet for options.

Assuming that a nutritionally balanced diet can be made without using any concentrated supplements – Many pet owners who want to cook for their pets make that decision because they are concerned about certain pet food ingredients and want to feed their pets food that contains only healthy ingredients that they recognize. So, the idea of adding purified vitamin and mineral supplements to the food, whether the supplements are made for people or animals, may not fit with their perceptions of a homemade diet. Along with this misconception is the idea that people eat nutritionally balanced diets without adding supplements, so why would pets need them? The truth is that most people don’t actually do that good of a job eating a balanced, nutritious diet. While blatant nutrient deficiencies aren’t common in the US, many chronic diseases that are known or suspected to have a dietary component are very prevalent – obesity, atherosclerosis, type 2 diabetes, and many other diseases could be prevented or mitigated with closer attention to diet in people. Our pets deserve to be fed a nutritionally balanced diet! As commercial pet foods are designed to provide all essential nutrients, we design homecooked diets to also provide all essential nutrients so there is never the concern that a pet isn’t getting what it needs. And providing a consistent amount of all essential nutrients in a recipe that is not time- and cost-prohibitive to make requires the use of concentrated supplements to fill in the gaps between the main ingredients. In a survey of previous clients of the Nutrition Service here at Tufts, we found that only 13% of clients were following the original recipes that were prescribed 6-12 months later! A common change that was made was adjusting or leaving out the supplements, which can result in a very unbalanced, unhealthy diet. Therefore, it is absolutely essential that you make the recipe exactly as the nutritionist designed it, including all the supplements in the specified amounts!

Changing the cooking method or substituting ingredients – different cooking methods result in differing nutrient amounts. So, changing cooking methods – boiling instead of baking, using a crockpot to cook all ingredients together instead of cooking them separately as stated in a recipe – or swapping ingredients can have big effects on the nutrient profile of a diet. For example, baking potatoes instead of boiling results in ~20% higher potassium concentrations. Adding all the ingredients to one pot as raw ingredients and cooking them together can result in very different calories as well as some nutrients compared to if the ingredients were cooked separately and then combined. Swapping ingredients can also cause homemade diets to diverge from the intended nutrient profile. For example, if the same volume or weight amount of sweet potatoes are used instead of white potatoes in a recipe, that will result in a ~60% increase in calories.If specific cooking methods are desired, it’s important to let the nutritionist know ahead of time so they can select the correct cooking methods in their software and you end up with a recipe that accurately reflects the nutrient profile of the diet being made. Similarly, it’s important to ask about ingredient swaps before making them to make sure that the swap won’t result in inappropriate amounts of calories or nutrients. If you change the recipe in any way, the diet may no longer be meeting all of your pet’s nutritional needs. Never change a recipe without talking to the nutritionist who formulated it!

Not adjusting all ingredients in a recipe when adjusting calories – Nutritionists try to make recipes that will provide appropriate calories for a specific pet but this can sometimes be challenging since individual pet’s metabolic rates can vary. If there is inadequate information about the pet’s previous calorie intake or medical factors that alter calorie needs, that forces the nutritionist to use their best judgement and that may result in weight gain or weight loss. Pet owners will often try to adjust the recipes themselves without talking to their veterinarians or their veterinary nutritionists. Often they do this by decreasing or leaving out the fat ingredients, decreasing the carbohydrates only, or only increasing the protein or fat. While all of these actions will change the total recipe calories, they can also dramatically change the nutrient profile of the diet. If a recipe needs to be increased or decreased in calories and a nutritionist isn’t available to help, the best option is to take the recipe and mathematically increase or decrease the amount of EVERY ingredient proportionally. For example, every ingredient in the recipe can be increased by 10% if a pet is slowly losing weight on the recipe. The easiest way to do this is to use the amount of each ingredient in grams – it can be a challenge to increase volume measurements accurately by small amounts. If 100 grams of chicken are being fed, 10% more would be 110 grams. If 2 & 1/4 cups of rice are being fed, 10% more is much more difficult to figure out and may not result in an amount that is easily measured. Any oils and supplements should also be adjusted by the same percentage, along with the protein and carbohydrate ingredients as well as any other ingredients, to keep the whole diet proportional. If this sounds too complicated, be sure to talk to your veterinarian or the veterinary nutritionist who formulated the recipe for guidance for advice to avoid making changes to your pet’s diet that could be harmful.

If you are cooking for your pet, do any of these issues sound familiar? Veterinary nutritionists have your pet’s best interests in mind when we design homemade diets and we want you to be happy with our services and for your pet to thrive. To get the best results from a consultation with a veterinary nutritionist as well as a homecooked diet formulation, it is important to tell the nutritionist your specific preferences/needs ahead of time and then follow the recipe exactly to ensure your pet is getting all the necessary nutrients in the right amounts to keep them healthy or manage their health issues. If you feel that changes are needed, always seek veterinary advice!

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Cailin R. Heinze, VMD, MS, DACVIM (Nutrition)

Dr. Cailin Heinze is a Board-certified Veterinary Nutritionist® and the Executive Director and Chief Academic Officer of the Mark Morris Institute, a non-profit organization whose mission is to promote optimal companion animal health by providing educational opportunities for veterinary students and veterinarians in clinical nutrition. She has also done some consulting work for Balance IT, a company that makes software and supplements for home-cooked pet diets. She is an expert in home-cooked diet formulation and general pet nutrition and has a special interest in feeding pets with kidney disease and cancer.