An ambitious 21-year-old woman who weighs nearly 400 pounds embarks on a one-year challenge in hope of losing weight.

A 23-year-old man tries to fulfill a promise he made to his late mother to lose weight and lead a healthier life.

45-year-old bachelor Dana tries to lose weight and reclaim his life.

Weighing in at 651 pounds, James, a 25-year-old former football player from Fort Worth, Texas, becomes the most obese person trainer and transformation specialist Chris Powell has ever worked with. James must lose 150 pounds to stay on track in the first of his four, three-month phases of weight loss.

A young woman works to lose weight and in the process must face the secret that lead to her becoming obese

Wally, 26, a young father who weighs 490 pounds and whose wife is uncertain if her husband will be around to see their daughter grow up.

Staci, 30, a 456-pound married mom caring for her husband and their two young children, while doing her best to keep a positive outlook.

Krista, 34, a devoted mother whose care for her developmentally-disabled daughter has taken a tremendous toll on her 445-pound body.