How Much to Feed a Dog - A Science-Based Guide

As a veterinarian, “how much to feed a dog” is probably the most common question I’m asked during wellness exams. While some owners assume this to be straightforward, it’s actually a more difficult question to answer accurately.

In this article on how much you should feed your dog I will explain why the answer is not that simple and I hope it will help pet owners make better, informed calculations for dog food portion sizes.

Accurate Portion Estimations

Obesity in dogs is the most common nutritional disorder diagnosed, with estimates ranging from 25% to 40% of pet dogs being affected (1, 23, 4). Since obesity is directly related to calories consumed, how much to feed a dog is of critical importance.

Preventing obesity by not overfeeding is the number one best way to keep dogs healthy and promote longevity. A study in the British Journal of Nutrition found that dogs kept at a lean body condition lived on average two years longer than their overweight counterparts (5).

In addition, onset to diseases compounded by obesity were delayed when compared to onset in dogs with a thinner body condition (3, 67).

Dogs are an extremely difficult species to generalize energy requirements for due to the enormous variation in size, body types and activity levels seen in different breeds. Calories needed can even vary among dogs of the same size and breed due to age, whether spayed or neutered and muscle mass among several other factors (8, 9).

Summary: Measuring perfect amount of food for the dog can prevent diseases and increase longevity, but the amounts must be assessed (by pet owners or vets) for each individual dog rather than using a “one size fits all” formula.

Guidelines on Dog Food Labels

Recent guidelines put forth by the American Association of Feed Control Officials (AAFCO) in 2013 requires dog food manufacturers to list the calorie content of the diet. This allows pet owners to make more informed calculations regarding portions.

Further complicating the issue of how much to feed a dog, however, is the fact that dog food varies significantly in calories per cup of kibble.

Some diets, such as Fresh Pet Select, have as few as 226 calories per cup, whereas other brands, such as Innova Holistic Large Bite, have as much as 537 per cup. This means that one cup of one type of food could have as much energy as 2 cups of another.

Careful evaluation of the energy density of the diet you are feeding is paramount to controlling calorie consumption since there is such a range.

The calorie content statement displayed on the dog food label is generated either by complex calculation or by digestibility trials.

Summary: Dog foods vary in their composition, thus each brand must be re-assessed for proper feeding amounts.

Do Not Use Dog Food Labels Alone

When calculating calorie content using an equation, it is easy to underestimate calories in highly digestible, high quality foods and overestimate calories in poorly digestible, lesser quality dog foods.

Therefore, digestibility trials are a much more accurate way to determine calorie content as described by the AAFCO’s publication “The Business of Pet Food.”

In addition to calories per cup, feeding directions are also required on dog food labels. They are generally listed by recommended cups of kibble per body weight.

These feeding guidelines are extrapolated from research done on canine energy requirements by the National Research Council (NRC).

There are many studies suggesting the amounts listed on the labels of dog food are overestimated, however (11, 12, 13).

This may be related to the fact that many dogs are more sedentary than dogs used in the research. There is some suggestion that the NRC is unable to account for the enormous variation in requirements among different breeds (14).

The feeding guidelines are also assuming that the dog food is the only source of nutrients the pet is being fed. This tends not to be true, as many owners feed treats, raw hides, dental products, and table scraps. When other sources of calories are fed, dogs will require less kibble. Many owners don’t realize how quickly those extra calories add up.

Summary: Portion and feeding guidelines on dog food labels are not always accurate.

Formula for Feeding

Given the fact that there is so much variation in calorie requirements and equally as much variation in calorie content and even variation in calorie content determination, you start to see how complicated the answer to the “easy question” of how much food to feed a dog is.

Scientifically, the equation for energy requirements in dogs is defined as:

Resting Energy Requirements measured in Kcals per day = 70(Body Weight in Kg)^0.75. This equation should give the minimal calories needed for resting.

Studies show that dogs can vary as much as 50% above and below the calculated average for energy requirement depending on age, breed and activity level (78, 9).

Realistically, most owners are not going to be able to sit down with a calculator to figure this out. Therefore, a more realistic approach to figuring out how much to feed a dog is to examine the feeding recommendations on the dog food label, and use these as a guideline.

Summary: Using a dog food label guidelines with individual dog’s energy requirements formula is the most accurate way to figure out how much to feed a dog.

Lean Feeding

As a veterinarian, when you ask me how much you should feed your dog, my careful answer to this complicated question is: feed enough. Let me explain this.

Learning to ‘lean feed’ your dogs is the best way to determine the correct amount to feed. Use the label on the dog food bag as a starting point, keeping in mind that this amount is often overestimated.

It is also important to feed the amount listed for your dog’s healthy weight; NOT their current weight if they are too heavy. Then you feed this amount and monitor your dog’s body condition very carefully.

A dog with a normal, healthy body condition should have a defined waist when viewed from above (use the BCS chart for reference). The abdomen should tuck upwards from the margin of the ribs to the hips when viewed from the side. Ribs should be easily palpable, but not prominent.

An overweight dog has a layer of fat covering the ribs, making them hard to palpate. The waist extends straight from the margin of the chest through the hips without indenting when viewed from the side. When viewed from above, an overweight dog lacks an hourglass shape.

If your dog seems to put on weight with this amount, then reducing by 20% is generally advised. If ribs seem more prominent after several weeks, increasing by 20% is advised. Don’t be alarmed if your dog requires an amount much different from the amount listed on the label.

Lean feeding is a great skill to have since dog’s energy requirements change over time and even with the seasons. By always being aware of your dog’s body condition, you can prevent obesity by constantly monitoring and calculating portions.

Summary: Using Body Condition Score chart to monitor pet’s bodyweight and size, and adjusting the portion control based on that (using labels and formula above) is the best way to keep the dog in top shape.