Some pets need to eat more than others to maintain their body weight, others put on weight easily.

This is due to:

differences in activity level/lifestyle
differences in breed
stage of growth
individual metabolic rates
external factors such as temperature

Dog owners should use a Pet Size-O-Meter every 2 weeks, or weekly if worried about their pet’s bodyweight and regulate the food accordingly. Advice about weight loss or weight increase in pets can be obtained from your veterinary surgeon and any concerns you have about your pet’s body condition should be addressed.