A study done in the U.K. demonstrates this as it highlights that there is statistical variation between dogs and their needs, based on their individual genetics. With a group of 7 dogs of the same breed, sex and age, it showed that 1 in those 7 will need about 25% more calories than the average, and 1 in those 7 will need about 25% fewer calories than the average – thus it is right that dogs be treated as individuals with individual needs where diet is concerned. 

More than 200 congenital or genetic disorders have been reported in dogs and some of these have an effect on the way the body is able to process nutrients. Differences can be seen perhaps more clearly in the obvious differences between different breeds in dietary needs;  i.e. many pet dogs are fine and show no ill effects when eating meat which has been frozen for long periods, however, in this same situation, sled dogs in the Antarctic developed scurvy, a condition which was rectified upon giving them extra supplements of vitamins to prevent the decrease of plasmaconcentrations of vitamin c in their diet so obviously needed in higher amounts by their bodies due to the genetic disposition and way they have been bred for the work which they do.