It is very important to keep our dog at an adequate weight. Unless your vet advises otherwise, you should try and keep your dog in the weight-range typical for his or her breed and gender.
Here we present a chart of the weight distribution for Labrador Retriever dogs. The weight of a typical female ranges from 22.4kg to 34.8kg and that of a male from 28.7Kg to 38.7kg. That is, 49.4lbs to 76.7lbs for females and 63.3lbs to 85.3lbs for males.