The Dr they had as a guest has prescribed the drugs frequently and made several good points, but principal among them was that the drugs are only a tool and you need to get your house in order in terms of diet and exercise or its a waste of time in writing the script.
Basically regardless of what a person's excuse might be for obesity (metabolism, the food industry, compulsive behavior), the individual simply has to man the fuck up and accept responsibility. Always giving yourself an out by falling back on the excuse is a huge mental roadblock for people that will be a thorn in the side of progress IMO.