Energy metabolism in the dog must be properly understood by anyone attempting to train and breed sleddogs. It is not the same as human energy metabolism. In the human species, energy metabolism is primarily fueled by carbohydrates. Carbohydrates do play a role in canine energy metabolism, but that role is minor compared with the role of fats, which are used directly by dogs in the form of "free fatty acids." (In human metabolism fats must be broken down into carbohydrates before they can be utilised.) Free fatty acids contain 2.5 times as much energy as either carbohydrates or proteins, and the dog is much more efficient in his fat metabolism than most other species.

Consequently working sleddogs should have the fat content of their rations adjusted both for ambient temperatures and for workload. That is not easy to do just on prepackaged commercial dog kibble; for this reason most serious dog drivers either supplement commercial rations, or develop their own home-prepared rations.