I am about to do this with a client. As any trainer knows its impossible for change to happen without a solid support system. So what happens when a trainer gets a client with health issues that are directly related to obesity and has no developed support system? Its an easy answer. I am going to get my client to list 3 of her closest friends/family then sign an agreement with them stipulating that they understand that she is undergoing a lifestyle change and that they will in no way interfere or sabotage her, but will instead encourage her and take necessary action should they see her showing signs of weakness.
Something along those lines.