Fitness and lifestyle expert, Jackie Warner, begins “Thintervention” with eight pampered clients who are unhappy with their weight. After a basic training workout in order to assess their fitness levels, the clients are told to remove all sugar from their homes. To ensure that her new policy is enforced, Jackie visits the homes of the cast the next day, only to find that most haven’t complied with the rules of their assignment. The following afternoon, Jackie introduces her extreme workout, an intensive outdoor obstacle course that pushes the clients to their limits. On day four of the program, trouble begins to brew when Jackie discovers that some clients still haven’t eliminated sugar from their diets. The new clients undertake an emotional group therapy session in which clinical psychologist Dr. Ramani helps them confront the causes of their overeating. Following therapy, the clients conduct their first weigh-in.