British Shorthair cats are considered adults at 12 months of age or older, which is equivalent to a human between 16 and 18 years old. During this time, their weight will gradually increase until they reach maturity, at which point their weight will remain constant. Adult males typically weigh around 5 kilograms, while females typically weigh around 4 kilograms. 
Feeding methods for adult British Shorthair cats:
1. Diet. Adult British Shorthair cats can start eating adult cat food, but when changing cat food, it is best to use the seven-day transition method. British Shorthair cats have relatively poor digestive function, and sudden changes in cat food can lead to diarrhea and other problems.
2. Exercise. British Shorthair cats don't like to exercise and are prone to obesity. Overweight cats can also experience health problems. It is recommended to exercise and play for at least half an hour every day to maintain their health.
3. Cleaning. Cats have a habit of cleaning themselves with their tongues, but they also ingest a lot of hair. Regularly feeding them hairball paste can help clean up hairballs in their intestines and also help care for their digestive system.
