After exercise (cardio or weights), your muscles need to be given the proper nutrition to ensure recovery. Otherwise, you risk muscle catabolism.

As for the anti-asthmatic meds for weight loss, he is referring to Clenbuterol. It isn't available in the US. There are some others that can be used for that, but they are very short acting and only present a tiny amount of fat loss over the standard ephedrine/caffeine stack ... but the asthma meds (besides being illegal) have many more side effects.

On a personal note, I would be wary of any trainer that is pushing drugs on their clients. It is unethical, and I am sure that he can lose his job for that.

There are many ways to naturally and legally manipulate your metabolism to enhance fat loss without using illegal medications.

Having said that, this forum is not to be used to discuss using prescription meds for weight loss. The only meds that the FDA has approved for weight loss (currently) are Meridia and Xenical. Those are the only ones I will discuss, but they both are only maginally effective.