I doubt that is a real factor. There may be a slight change in metabolic rate from Beta blockers but increased appetite and more eating is the cause of most all other drug side effects. And, metabolic rate differences is a myth, or more accurately an excuse. Fat people use most of their calories keeping a poorly insulated bag of mostly water at almost 100 F all the time. And, some calories consumed by movement.
Insulin causes weight gain. It can even cause edema. Corticosteroids not only affects metabolism but causes the body to retain salt and water leading to fluid retention and bloating. I know what I’m talking about, you don’t.