By the time a dog is 12 to 18 months old, most dogs would have reached their full size although it does take longer for some of the largest breeds to nish growing. At this adulthood stage i.e. age 1 year to 6 years old, you will notice your dog’s nutrients and physical needs will have changed. Hence, it is important to note that your dog will need a grown-up food to provide him/her with all the nutrients, vitamins and minerals s/he needs to maintain his/her health for a long and happy life.