Eleven teams will be competing in the new season of "The Biggest Loser," and their combined weight is more than 3.5 tons!

This year, the theme is on "Couples," but not just husbands and wives. There are cousins, best friends, sisters, mothers and daughters, a father and son and an engaged couple. Among that group are the heaviest-ever woman (identity to come), the heaviest-ever contestant (Daniel Wright who weighs 454 pounds), the youngest-ever contestant (Mike Morelli at 385 pounds) and the oldest-ever couple (63-year-old grandparents Estella and Jerry Hayes).

"I think it's really interesting when we really delve into couples because when you're working with parents and their children, you really see the guilt that the parents have when it comes to what they've done to their child," trainer Bob Harper tells ET. "And I think that it becomes very inspirational, too, because we try to show them that no matter how bad it's gotten, no matter where their path is, we show them a way that we can get them back on track."

"The Biggest Loser" tries to find the healthiest possible morbidly obese folks for their show -- all of whom are put through a physical prior to beginning the weight-loss program. But even so, the show takes precautions.

"We have medics on site whenever we are training them," Bob continues. "So we keep all of our bases covered when it comes to the health and welfare of the contestants."

The new teams competing for the $250,000 grand prize include:

BEST FRIENDS:

Carla Triplett (Assistant bank manager), 36, and her best friend Joelle Gwynn (Non-profit founder), 41, Southfield, MI.

Daniel Wright (Student), 19, Willow Spring, NC, and his best friend, David Lee (Student), 23, Fuquay-Varina, NC.

COUSINS:

Sione Fa (Owner, landscape company), 28, Maricopa, AZ and his cousin, Filipe Fa (Lube technician), 26, Mesa, AZ.

Blaine Cotter (College counselor), 27, Gilbert, AZ and his cousin Dane Patterson (Real estate appraiser), 27, Mesa, AZ.

ENGAGED COUPLE:

Damien Gurganious (Industrial designer), 31, and his fiancée Nicole Brewer (Wardrobe stylist), 37, Brooklyn, NY.

FORMER MODELS:

Tara Costa (Model/Finance manager), 23, New York, NY, and her friend Laura Denoux (Model/Sales director), 24, Miami, FL.

FATHER/SON:

Ron Morelli (Retired food distributor, currently City Councilman), 54, and his son, Mike Morelli (Student), 18, South Lyon, MI.

GRANDPARENTS:

Estella Hayes (Retired nurse), 63 and her husband, Gerald "Jerry" Hayes (Retired engineer), 63, Wheaton, IL.

MOTHER/DAUGHTER:

Helen Phillips (Retired retail manager), 47, Sterling Heights, MI and her daughter, Shanon Thomas (Massage therapist), 29, Centerline, MI.

Cathy Skell (Title sales closing agent at real estate firm), 48, Shiocton, WI and her daughter, Kristin Steede (Business owner), 28, Greenville, WI.

SISTERS:

Amanda Kramer (Cosmetologist), 30, Boise, ID, and her sister, Aubrey Cheney (Information and education specialist), 28, Gooding, ID.