Basics of dog energy requirement

A dog requires daily energy for (1)  Internal body functions essential for survival like digestion, and breathing (known as Resting Energy Requirements - RER) and (2) External functions like exercise, lactation, etc. (known as Daily Energy Requirements - DER).

This energy in a dog’s diet comes from three nutrients: fats, carbohydrates, and proteins. Energy is expressed in either kilocalories (kcal) or kilojoules (kJ): 1 kcal equals 4.184 kJ.

You must calculate the daily calorie requirements for your dog but remember the numbers depend on multiple factors and may change in your specific case. So, before changing your dog's calorie intake, always benchmark the current calorie intake, health, and weight status.

Steps to change your dog’s diet

1. Understand the current diet - Energy or caloric profile, current health status, number of meals in a day, current weight, and BCS score

2. Understand the ideal state - Research and build a perfect diet profile for your dog. That will fulfil your dog’s calorie and nutrition requirements.

3. Make the change gradually -  Introduce the new diet and phase out the existing diet gradually with changing proportions of new and old

STEP 1: Calculate Resting Energy Requirements (RER)

The first step in calculating your dog's calorie requirement is to calculate the dog's resting energy requirements (RER). The RER is the energy needed to maintain basic biological functions such as digestion, heart rate, etc. in an all-day resting state. RER forms the base of your dog's calorie requirement.

Formulas:

1. Calculating Resting Energy Requirements (RER) in English units 

   1. Body weight in LBS / 2.2 =  body weight in kg

   2. 70 * (body weight in kg) ^ 0.75 = RER

2. Calculate RER in metric unit

   1. 70 * (body weight in kg) ^ 0.75 = RER

Remember, RER does not factor in your dog's activity level and special needs.

Once the RER is identified then daily energy requirements (DER) can be calculated by adding calories needed for daily activity and special needs. The National Research Council (NRC) of America provides guidelines for how to adjust the RER based on the various energy needs of dogs.

STEP 2: Calculate Daily Energy Requirements (DER)

The formula for DER:

Daily Energy Requirements (DER) = RER * Multiplier

See the table below to find the appropriate multiplier for the dog’s special needs.

Remember these adjustments and calculations are for adult dogs only and do not apply to growing puppies.

Once the appropriate multiplier is identified, DER can be calculated by multiplying the dog’s RER energy requirements with the multiplier.

Convert the daily energy requirements to the amount of food

For commercial foods with calorie details:

Once DER is calculated, the daily food intake can be calculated by looking at the dog food label and getting the appropriate amount.

Consider your dog food label saying 3610 kcal/ kg or 415 kcal per 8 fl. Oz. cup. DER calculated is 830 cal per day. That means, 830/3610 kg of food per day. That will be 0.23 kgs or 230 grams of food per day. Or 830/415 of 8 fl.oz cup ⇒ 2 cups of 8fl. Oz. cup

If you feed homemade food (well done!!), use the human meal planning apps to calculate the calories you feed by choosing the various ingredients and their amounts. 

Our web app UnoDogs will help you do this calculation and much more. 

For fresh raw and cooked home food:

Daily amounts can also be calculated using the estimation method below. 

On average, 19-20 ounces (538-567 grams) of fresh food equates to 1000 calories. 

Three nutrients in the diet contribute to energy: fats (lipids), carbohydrates, and proteins. Out of these three nutrients, each has its range.

The fat component in the food has the highest calorie concentration followed by protein and then carbohydrates. Lower-fat diets will look more in volume and higher-fat diets will look less. Use this information to adjust your dog's diet volume.

Once the DER is calculated, the dog’s daily intake can be estimated. Divide the dog’s calorie requirement by 1000. Then multiply the result by 19-20 ounces (538-567 grams).

Calculations:

1. Calculate estimated daily Intake

   1. DER / 1000 kcal Baseline = Conversion variable

   2. Conversion variable * 20 oz weight baseline = daily food volume

2. Calculate estimated daily intake in metric units

   1. DER / 1000 kcal baseline = Conversion Variable

   2. Conversion Variable * 550 g weight baseline = daily food volume 

Some people also find using human meal apps for calorie estimation easy.