Limiting user from changing its own attributes

In PostgreSQL a user can alter itself to change its user level parameters. e.g. I can alter the user to change work_mem - 

psql -U user1 -d postgres

postgres=# alter user user user1 set work_mem to '1024000';

ALTER ROLE

postgres=#

Is there a way I restrict this behavior? or atleast put a restriction on the certain parameters e.g. work_mem to be not set to too high?

regards

Sameer