In the season premiere, Michaels travels to Wilmington, Mass., where she meets the Mastropietro family. She discovers the father already had an unsuccessful gastric bypass surgery and the mother has the same surgery scheduled, as they both hope to walk their daughter down the aisle later this year. As Michaels pushes the family outside of their physical and emotional comfort zones, she uncovers a deep-rooted and upsetting issue from their past that has been the main obstacle to their living a happier and healthier life.

The Jones family needs a jump start after a tragic loss.

After a father loses his job, Jillian motivates him and his family to get their life in order.

Jillian helps a family stay afloat and live a healthy life after a man closes his roofing business due to knee injury and heart problem.

Dolores Plunkett and her daughter, Coralie, are two of three cultural leaders of their tribe, the Yavapai-Apache Nation. Both want to see a change in their family's unhealthy diet (the result of snacking and convenience), and to help improve the health of their tribe. Jillian travels to Camp Verde, Arizona and joins the family in a traditional Yavapai welcoming ceremony and Apache dancing and shows them that there are still ways to be traditional and stay healthy at the same time by roasting an agave plant and planting corn. Dr. Katja Van Herle also stars.

Jillian Michaels moves in with parents of a Huntington Woods, Michigan home. Jillian's goal is to show them that even though they have been overweight all their lives they can make a change now and have a healthier lifestyle.

Part of a large, close-knit Cuban extended family, David Sr. and Carmen Alvarez have an obstacle in their way that they need to overcome. Their 9-year-old son, David Jr., is already pre-diabetic and on his way to health complications due to his weight. Unfortunately, David Sr. is also overweight, but he fails to see it as a problem that needs to be fixed, which proves to be a bad influence on his son who idolizes him. In order to help the family succeed, Jillian takes the parents on a boat to get them to open up about their health and lack of communication which hopefully will kick-start a new way of life for them. Dr. Katja Van Herle also stars.