Canine Obesity: Why Calories (and Nutrients) Matter
Canine obesity is a growing problem, with an estimated 30–56% of dogs classified as overweight or obese. While lack of exercise plays a role, the way we feed our dogs—especially when it comes to calorie density and nutritional balance—is a major contributor.
The Calorie Density Problem
One key factor is the wide variation in calorie density across dog foods. Dry foods can range from 200 to 660 kcal per cup—most falling between 350–450 kcal per cup. Foods on the lower end of the range are typically formulated for weight loss or weight management.
Fresh and raw foods can vary even more, from 28 kcal per ounce (448 kcal per pound) to 68 kcal per ounce (1,088 kcal per pound).
This makes it essential to check the caloric content every time you change foods, even within the same brand, to avoid unintentionally over- or underfeeding.
Unfortunately, there’s no universal feeding guideline to address this, and some brands don’t even adjust their recommendations across products with very different calorie densities.
This makes it essential to check the caloric content every time you change foods, even within the same brand, to avoid unintentionally over- or underfeeding.
Unfortunately, there’s no universal feeding guideline to address this, and some brands don’t even adjust their recommendations across products with very different calorie densities.
Why the Math Matters: Atwater vs. Modified Atwater Factors
Another hidden contributor to obesity is how calorie content is calculated. Some brands use the Atwater Factors, while most use the Modified Atwater Factors.
For example, a food with:
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10% moisture
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7% ash
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31% protein
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18% fat
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4% fiber
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30% carbohydrates
Would be listed as:
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406 kcal/100g (Atwater)
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366.5 kcal/100g (Modified Atwater)
That’s a difference of 39.5 kcal per 100g—or approximately 1 lb of weight gain every 88 days without anyone noticing.
Many foods may be underestimating actual calories if they rely on Modified Atwater, leading to overfeeding and gradual weight gain.
Caloric Restriction Nutrient Deficiency
Nutrient Deficiencies & Caloric Restriction
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. Based on data we have collected, many dogs are being fed at or below 95 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.
While much of the focus on DCM has been about Grain-Free, one aspect overlooked by most is that many of the dogs were consuming nowhere close to 130 Kcals that AAFCO is based on. Some of the dogs were consuming at or below the resting energy requirement for their weight. Meaning there is a strong possibility that they were also suffering from some nutritional deficiencies.
Adult Maintenance Diets: Nutrient Deficiencies
When we reviewed the nutrient profiles of 27 commercial dog food brands deficiencies were commonly found when fed below 95 kcal/kg BW⁰·⁷⁵
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Choline
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Vitamin E
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Pantothenic acid
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Riboflavin
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Thiamine
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Vitamin D
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Potassium
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Magnesium
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Manganese
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Zinc
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Iodine
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Selenium
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Methionine
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Methionine + Cystine
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Phenylalanine
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Phenylalanine + Tyrosine
Weight loss and weight management foods generally do better, but deficiencies still occur—most notably in:
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Choline
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Potassium
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Magnesium
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Selenium
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Methionine & Methionine + Cystine
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Phenylalanine & Phenylalanine + Tyrosine
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.
Reducing calories should never mean reducing essential nutrients.
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.
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. This 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 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.
If it is determined that you need to feed closer to the resting energy requirement to help your dog lose weight, then it is ideal to consult with a veterinary nutritionist to help come up with a diet plan so as to avoid nutritional deficiency,
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.
Studies
Linder DE, Freeman LM, Morris P, German AJ, Biourge V, Heinze C, Alexander L. Theoretical evaluation of risk for nutritional deficiency with caloric restriction in dogs. Vet Q. 2012;32(3-4):123-9. doi: 10.1080/01652176.2012.733079. Epub 2012 Oct 15. PMID: 23066734.
German AJ, Holden SL, Serisier S, Queau Y, Biourge V. Assessing the adequacy of essential nutrient intake in obese dogs undergoing energy restriction for weight loss: a cohort study. BMC Vet Res. 2015 Oct 7;11:253. doi: 10.1186/s12917-015-0570-y. PMID: 26446678; PMCID: PMC4597434.
Grant CE, Shoveller AK, Blois S, Bakovic M, Monteith G, Verbrugghe A. Dietary intake of amino acids and vitamins compared to NRC requirements in obese cats undergoing energy restriction for weight loss. BMC Vet Res. 2020 Nov 7;16(1):426. doi: 10.1186/s12917-020-02649-0. PMID: 33160364; PMCID: PMC7648986.
Keller E, Sagols E, Flanagan J, Biourge V, German AJ. Use of reduced-energy content maintenance diets for modest weight reduction in overweight cats and dogs. Res Vet Sci. 2020 Aug;131:194-205. doi: 10.1016/j.rvsc.2020.04.019. Epub 2020 May 1. PMID: 32388022.
Linder DE, Freeman LM. Evaluation of calorie density and feeding directions for commercially available diets designed for weight loss in dogs and cats. J Am Vet Med Assoc. 2010 Jan 1;236(1):74-7. doi: 10.2460/javma.236.1.74. PMID: 20043803.
German AJ, Holden SL, Bissot T, Hackett RM, Biourge V. Dietary energy restriction and successful weight loss in obese client-owned dogs. J Vet Intern Med. 2007 Nov-Dec;21(6):1174-80. doi: 10.1892/06-280.1. PMID: 18196722.
Weber M, Bissot T, Servet E, Sergheraert R, Biourge V, German AJ. A high-protein, high-fiber diet designed for weight loss improves satiety in dogs. J Vet Intern Med. 2007 Nov-Dec;21(6):1203-8. doi: 10.1892/07-016.1. PMID: 18196727.
German AJ, Holden SL, Mather NJ, Morris PJ, Biourge V. Low-maintenance energy requirements of obese dogs after weight loss. Br J Nutr. 2011 Oct;106 Suppl 1:S93-6. doi: 10.1017/S0007114511000584. PMID: 22005443.
Coe JB, Rankovic A, Edwards TR, Parr JM. Dog owner's accuracy measuring different volumes of dry dog food using three different measuring devices. Vet Rec. 2019 Nov 16;185(19):599. doi: 10.1136/vr.105319. Epub 2019 Aug 13. PMID: 31409751; PMCID: PMC6902066.
Wakshlag JJ, Struble AM, Warren BS, Maley M, Panasevich MR, Cummings KJ, Long GM, Laflamme DE. Evaluation of dietary energy intake and physical activity in dogs undergoing a controlled weight-loss program. J Am Vet Med Assoc. 2012 Feb 15;240(4):413-9. doi: 10.2460/javma.240.4.413. PMID: 22309013.