Dog Weight Loss Plans and Nutritional Deficiencies

Before starting a weight loss plan for your dog, it’s important to rule out other health issues first.

Canine Obesity

Canine obesity is a significant problem, estimated to impact around 30-56% of all dogs.   

One contributing factor in canine obesity is that dog foods have a diverse range of energy densities. On the lower end, for dry food, it can be in the 200’s kcals per 100 grams (approximately 1 cup) to 660 kcals per cup. Most foods fall between 350-450 kcal per cup. Which is still a sizeable difference. Most of the dog foods in the 200’s kcal per cup are foods formulated specifically for weight management or weight loss.

Fresh Foods range from 28 kcals per ounce (or 448 kcal per pound) to 68 kcals per ounce (or 1088 kcal per pound).

It’s so important always to check the caloric density of the food anytime you switch foods, even within brands, so you don’t end up over or underfeeding your dog or cat.

In an ideal world, feeding guidelines would help address this issue, but there is no set standard, and some brands don’t even have consistent feeding guidelines for their own foods with different caloric densitites. 

Another complicating factor is that a couple of brands do utilize Atwater Factors, while most use the Modified Atwater Factors. There is a growing body of evidence that the Modified Atwater Factors underestimate the energy provided by the food. This is likely another contributing factor to canine obesity, as most brands use Modified Atwater factors. 

Why Atwater and Modified Atwater Matter

Example: A food that is 10% Moisture, 7% Ash, 4% Fiber, 31% Protein, 18% Fat, and 30% Carbohydrates.  A food-using Modified Atwater would report it at 366.5 Kcals per 100 Grams, while a food-using Atwater factor would report it as 406 kcals. Making a difference of 39.5 kcals per 100 grams between the two reports of the same food. 

What this means for the consumer is that you think you are feeding 366, but in reality your feeding 406 calories. This can make a huge difference overtime in whether your dog is gaining or losing weight.

Caloric Restriction Nutrient Deficiency

While very few foods are formulated to the bare minimum nutrient requirements, there is a risk of nutritional deficiencies when attempting to help your dog or cat lose weight.

While in the short term, it might not be a big deal, over a more significant period of time (which is often the case), it can cause complications and even potentially hinder the ability of the dog to lose weight.

Research has shown that many commercial diets formulated for adult maintenance do carry a risk of nutritional deficiencies, especially when used as part of a weight loss plan.

While there is variability in the specific nutrients and amounts that are deficient, there are some commonalities across foods and brands.

Our research points towards many dogs already potentially dealing with slight nutritional deficiencies as a result of the current nutritional guidelines, which assume a dog’s maintenance energy requirement is 130 Kcals per kg bw^.75.

If most foods were formulated closer to the minimums, it would likely be a much more significant and noticeable problem. Luckily, most foods are not formulated to the bare minimum.

FEDIAF, the European equivalent of AAFCO, has its nutrient guidelines based on assuming maintenance energy requirements of 95 and 110 kcals per kg bw ^.75. Which is much closer to reality based on our research into how much pet owners are feeding, especially dogs over 4 years old.

Adult Maintenance Diets

Below are the nutrients commonly found to be below the recommended amount in many foods when fed at or below 95 kcals per Kg Bw^.75. This involved reviewing the profiles of multiple foods from 27 different brands of dog food. (More or less, depending on how you count)     

  • Choline
  • Vitamin E
  • Pantothenic acid
  • Riboflavin
  • Thiamine
  • Vitamin D
  • Potassium
  • Magnesium
  • Manganese
  • Zinc
  • Iodine
  • Selenium
  • Methionine
  • Methionine+ Cystine
  • Phenylalanine
  • Phenylalanine + Tyrosine

Dog Weight Loss and/or Weight Management Foods

When looking at both prescription weight loss diets and diets advertised as weight management, they do a significantly better job of still meeting the micronutrient needs of dogs, with some exceptions.  

The nutrients that were most commonly deficient when feeding closer to a dog RER: 

  • Choline, Potassium, Magnesium, Selenium, Methionine, Methionine+ Cystine, Phenylalanine, Phenylalanine + Tyrosine

Vitamin A

Vitamin A is tricky to account for as brands don’t have to disclose how much vitamin A is pre-formed or in the form of pro-vitamin A.

While dogs can (Cats and other strict carnivores cannot) convert beta-carotene to Vitamin A RE. The conversion rate is not well established. Complicating this is the fact that research in humans and other animals shows that the conversion of pro vitamin A such as beta carotene to Vitamin A RE is influenced by multiple factors (Vitamin A status, amount of Vitamin A in diet, amount of fat in the diet, genetics, and body mass index).

So ideally, foods shouldn’t be relying on Vitamin A in carrots or spinach to meet the vitamin A requirement. There are other carotenoids, some of which have Vitamin A activity, while others do not. These; however, have not been extensively studied, and should definitely not be relied upon.


This is one area that needs significantly more research before plant-based dog food can be considered safe for adults’ long term, not to mention puppies or those who are pregnant or nursing.

Green Bean Diet For Dogs

There are veterinarians, and many websites that will recommend the green bean diet for dogs that need to lose weight, with some recommending up to 50% of daily calories with green beans.

While it might be fine in the short term, it should not be done in the medium or long term.

Just because a dog needs caloric restriction doesn’t mean they need nutrient restriction.

Replacing a portion of the complete and balanced food with green beans (unbalanced) will only cause and/or worsen any nutritional deficiencies. Especially when these are likely dogs that are struggling to lose weight at or below their resting energy requirement.

Developing a Weight Loss Plan

The first step in developing a weight loss plan is to determine the ideal body weight based on current body condition and muscle condition score and the amount of weight the dog needs to lose.

Next it should be attempted to simply reduce the current amount of food fed.

This is the first step because organ and muscle tissue are metabolically active, while adipose tissue is for the most part not metabolically active. So, it’s important to make sure that you are feeding enough to still meet those requirements.  While reducing energy is important, it doesn’t change the fact that the dog still has specific nutritional needs.

This is also why a weight loss plan should involve a veterinarian, especially if it requires feeding less than the Resting Energy Requirements. Which does happen, with some dogs only losing weight at 60 to 80% of their resting energy requirement. If consuming less than 60%, it's ideal to consult with a veterinary nutritionist to develop a diet for weight loss.

This is especially important for cats as aggressive caloric restriction can result in hepatic lipidosis (uncommon in dogs). This is why there has been such an interest in choline over the last couple of years, as the research so far indicates that increasing the amount of choline in the diet beyond the recommended amount lowers the risk of hepatic lipidosis in cats.

Weight Loss Nutritional Considerations

While weight loss can be done with a regular or light maintenance diet, special attention does need to be paid to the entire nutrient profile to avoid any deficiencies. Which can occur, as we discussed earlier, when feeding below 95 kcals per Kg Bw^.75.

Ideally, any food formulated for weight loss or weight management should be more nutrient dense than food advertised as being for adult maintenance.

However, one relatively large dog and cat food brand’s weight management food has relatively the same nutrient density as their regular foods for adult maintenance. 

Providing adequate amounts of protein is extremely important for dogs that need to lose weight, as it helps maintain lean body mass.

Another nutritional consideration that is commonly employed across foods formulated for weight loss and/or management is fiber.

By increasing the amount of fiber, it allows for the food volume to stay the same while still allowing for caloric restriction.  This is especially important as it reduces the amount of begging in most dogs. Making it significantly easier to stay the course instead of giving into a dog's begging eyes. 

Many foods will add in L-Carnitine. L-Carnitine is important for fatty acid metabolism as it transports fatty acids to the mitochondria which are used to generate energy. It has been shown that L-Carnitine can aid in maintaining lean body mass in dogs undergoing weight loss.

Before feeding based on a dog's resting energy requirement, it should be attempted to simply reduce the calories from what is currently fed. This has an additional benefit as it can help determine the dog’s actual maintenance energy requirement.

The calculator below will help you determine the amount of food to feed or determine your dog's resting energy requirements. This should help give you a range for your dog's maintenance energy requirement and your dog's actual maintenance energy requirement based on the caloric density of the food currently being fed, not including treats and supplements. More on that later.

The food should be weighed out during the dog’s weight loss plan instead of simply being measuring even when it is familiar, as research shows most of us are not very good at measuring.

Treats, Supplements, and Chews

Treats, supplements, chews and toppers should always be no more than 10% of daily calories. While this is important for all dogs, it’s even more important for those dogs losing weight as it increases the risk of unbalancing the diet.

Supplements, in particular, can often be a hidden source of calories, and not just fish oil. Many supplements make use of things like peanut butter, which is very high in calories. But more importantly, many supplements, particularly those in a chew/treat format, are generally at least 80% inactive ingredients with many are over 90% inactive ingredients. It is important to note that inactive ingredients are labeled alphabetically, not by weight.  With supplement treats/chews ranging between 2 and 6 grams  

Inactive Ingredients: Coconut Glycerin, Flaxseed, Garbanzo Flour, Mixed Tocopherols (a preservative), Natural Bacon Flavoring, Natural Flavor (from Oregano, Flaxseed and Plum), Natural Turkey Flavoring, Palm Oil, Pea Flour, Powdered Cellulose, Rosemary Extract, Sunflower Lecithin, Sweet Potato, Turkey.


A 30 lbs. dog in a weight loss plan receiving their resting energy requirements would be receiving ~496 kcals. So, 49.6 calories from treats, chews, and supplements, and 446.4 from food.

Looking at a popular dog supplement: While Natural Bacon Flavoring, Natural Flavor (from Oregano, Flaxseed and Plum), Natural Turkey Flavoring, Powdered Cellulose, Rosemary Extract do not contribute many calories. Coconut Glycerin, Flaxseed, Garbanzo Flour, Mixed Tocopherols, Palm Oil, Pea Flour, Sunflower Lecithin, Sweet Potato, Turkey, do add calories.

Conservatively, the 4-gram supplement above is probably at least 12 calories per supplement, or at least 24% of the dogs treat allowance. Their feeding guidelines also recommend 2 a day so at least 24 calories or 48% of the dog's daily treat allowance. Many owners also give multiple supplements each day, so you can see how quickly the calories from supplements can add up.   

Joint and skin coat supplements in particular will often be higher due to including things like green lipped mussels and fish oil.

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Our Treats

While we put an emphasis on treat size, that isn’t the case across the pet industry. We also place emphasis on making sure all of our treats are very lean, by picking lean cuts and also trimming the overwhelming majority of all fat.

We do offer freeze dried green beans that have been marinated in pork bone broth to improve the taste for dogs. What makes green beans great is that they are high in fiber, which is why the green bean diet spread, despite its nutritional shortcomings.

As we were writing this, we realized that we talked about the problem of nutritional deficiencies with weight loss, but we didn’t offer a solution.

This is why we will be releasing (in the near future) a supplement formulated to address the specific nutritional gaps for dogs with slow metabolisms or dogs undergoing caloric restriction as part of a weight loss plan.

The supplement will be formulated strictly to ensure that your dog is still receiving the recommended amount per the NRC for your dog’s ideal body weight, nothing more. Because despite the abundance of multi-vitamins in the pet industry most dogs don’t need them, and they just make for more expensive pee and poop.

So if your dog is consuming less than the 95 Kcals bw^.75, and maintaining weight or your dog is in the process of losing weight, then be on the lookout for when we launch it.

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When we launch the supplement, we are more than happy to discuss the supplement with your veterinarian.


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