Primer on Calories
A Primer on Calorie Expenditures.
In our last post, we discussed some of the common behaviors (in humans) that lead to an overweight dog and some tips on how to change them. Today, we will talk about calories and how your dog’s weight and activity level impact the amount of calories that are used each day.
Kcals– the standard unit. The following is one definition of calories, from the American Heritage Dictionary: “A unit of energy-producing potential equal to this amount of heat that is contained in food and released upon oxidation by the body.” Also called a nutritionist’s calorie, this unit, used in diet and weight calculations is in fact, a kilocalorie (kcal) or 1000 calories as defined above.
We like to define calories in four ways, basal, resting, activity, and total calories.
Basal Calories- are the required number of calories needed in order for the body to maintain its functions while at rest. Basal calories are commonly referred to in the context of the basal metabolic rate, or BMR- the rate at which your body burns calories while performing basic functions like respiration and other life critical functions. This means that the basal calorie burn is measured for a completely at rest body. Thus, almost all but the most bed-ridden and infirm dogs (and people) burn more than their basal calorie requirements because even the most lazy ones still will be up and about to some extent. The primary driver of basal calories burned is the weight of the dog. The larger a dog is, the more calories they will need for basal bodily functions.
Resting Calories- although some consider basal and resting calories the same, we actually make a slight distinction. While basal calories are measured against basic body functions when the body is completely still, resting calories include other non-strenuous, but normal and limited activities like walking outside to use the bathroom and getting up and down throughout the day to get water, food, etc. Resting calories are used as the baseline for all dogs other than those that are caged/infirm. The primary driver of resting calories burned is the weight of the dog. The larger the dog is, the higher the required calories will be for basal function and minimal activity around the house.
Activity Calories- are the calories that are burned while performing specific activities and exercise. These are the calories that you are able to control by taking your dog for a run or to the dog park and such. Although the weight of the dog does factor into the activity calorie calculation, the duration and intensity of the activity is the primary driver for calories burned. The longer the duration and the higher the intensity, the more calories will be burned, all else equal.
Total Calories- now that we have the components, we can define the most important calorie value which is the total calories burned each day by your dog. The equation is simple:
total calories burned = (basal or resting calorie burn) + activity burn
Normally, a caged or infirm dog will not have any activity burn and thus for them, total calorie burn = basal calorie burn.
The reason it is so important to have an idea of the number of calories that your dog burns is so that you can make sure that you are feeding them an appropriate number of calories each day and not too much or too little. As you may know from your personal dieting/exercise routines, a pound of fat stores 3500 calories. Thus, to lose a pound of fat a week a dog (or person) must eat approximately 500 fewer calories per day than he/she expends. When your dog is at their ideal weight, you would like to keep the equation in balance: calories burned= calories fed. Pretty simple in theory.
Now that we have the terminology straight, we can start to dive into some details and examples of calorie burns for certain scenarios. That is exactly our plan for the next installment. Stay tuned.