Sorry, but that just sounds like such a gimmick. Any class that incorporates cardio and weightlifting is going to help get you in shape (and lose jeans sizes) IF you do it regularly and eat right. It sounds like an okay class, but really it's just a marketing thing to imply that that class in particular will help you fit into skinny jeans. I suppose maybe the name helps to motivate people to go, but people should know that you can't just focus on spot training to get in shape or lose weight.