Dr. Nowzaradan tells Tara that if she doesn't change her eating habits immediately, she'll only live five more years. Tara is reduced to tears when her mother delivers an ultimatum on top of that.

Chuck is surprised to discover that surgery didn't take away his cravings. He's still getting meals from the drive-thru.

Moving to Texas wasn't easy for Christina, but she's kept a brave face. Daunted by getting into her temporary home, though, she breaks down into tears.

Christina is shocked to discover how little weight she's lost after surgery. Her family offers her some excuses, but she tells them it's simply not good enough and she has to work harder.

Zsalynn is scared going into surgery, but she puts on a brave face for her daughter Hannah. She confesses that she wishes her husband were there to support her.

Zsalynn fights -- and wins -- the battle over tortilla chips at a Mexican restaurant, but she later falls prey to another food craving.

Paula mentally prepares for gastric bypass surgery by drastically altering her look with bright green hair dye.

James comes from a long line of family obesity and at 706lbs, is determined not to die in the same hospital bed that his father and sister did.

Penny is transported from her home in Maryland to see Dr. Nowzaradan in a Texas hospital. Once she's there, he shares some grim facts about her weight and BMI.

These individuals transform their bodies -- and their lives -- over an intense seven-year journey.

Olivia is placed in the hospital for 48 hours to assess her preparedness for gastric bypass surgery.

Olivia travels from Chicago to Texas to see Dr. Nowzaradan, but the 18-hour car trip is grueling for someone in her condition.

Post surgery Zsalynn enjoys the next step in her battle with obesity, but her victory is short lived with the arrival of her unsupportive husband.

Paula is motivated to work out with a personal trainer at her gym, but it's still going to take some time before Dr. Nowzaradan's diet advice really sinks in.

Chuck weighs almost 700lbs and it has hindered every aspect of his life. He's had to downsize his business and his wife feels like a single-parent, who is ready to leave him.

Christina's husband and mother are enabling her to eat 7,000 calories a day. She learns a tough lesson from Dr. Nowzaradan: When they put food in front of her, she must simply say no.

Joe hits the gym for the first time, in an attempt to lower his weight from the dangerously high 800 pounds.

Lisa discusses her early childhood and how she got to this weight.

At 600 pounds, Lupe spent the last ten years in bed & totally dependent on her husband.

Watch Laura struggle to lose enough weight to become eligible for weight loss surgery.

We follow Joe on his wheightloss journey. He's already lost over 200 pounds

Robert struggles every morning with simple tasks due to his weight. Luckily, his fiancé, Kathryn, is there to help him get through the day.

Nicole describes her difficult childhood

Tamy describes her early childhood and how her family influenced her weight gain.

Charity weighs nearly 800-lbs. Suffering from flesh-eating bacteria and butterfly shaped fat deposits, she must have constant help from her family. When unexpected bad news threatens her weight loss journey, she must decide if she can continue.

Nicole explains how a trip to the grocery store is for her, and how she truly enjoys shopping for food.

Joe travels to Iowa to meet with his doctor and get an update on his health.

After Tamy has lost a significant amount of weight, she makes an effort to be more independent and decides to do the laundry on her own. Unfortunately, this simple task does not go as she hoped.

Nicole's weight restricts her from taking care of her children, causing her to rely on her mother for help.

Marla is so heavy she cannot stand up. Bedridden, her true weight is unknown but estimated at 800-lbs.

Brothers David and Benji discuss their early childhood and the stressors that led to their overeating.

Despite having lost 378lbs, Angel's knee pain combined with a history of obesity threatens everything she's worked for.