Teenagers who once spent sleepless nights worrying about things like prom, peer pressure and college applications are now facing a more serious threat—obesity.

Over the past 20 years, the Office of the Surgeon General says the number of overweight children has nearly tripled. This national epidemic is causing health problems that were once unimaginable for children. Now, adults aren't the only ones who have to worry about high blood pressure, diabetes and strokes.

According to The New England Journal of Medicine, the next generation of children may be the first in history to have a shorter life expectancy than their parents.

Many moms and dads aren't taking this news lightly…some are taking drastic surgical steps to help their obese teens lose weight. Even Food and Drug Administration regulations can't stop some parents. "Is this crazy or a dramatic intervention?" Oprah asks.
Cassie prior to her weight loss surgery.

Since some weight loss procedures like gastric banding aren't FDA-approved for children in this country, one mother traveled to Tijuana, Mexico, for help.

In 2004, Jennifer's 13-year-old daughter Cassie weighed 220 pounds. Though Cassie tried dieting and consulted a nutritionist, Jennifer says she kept putting on weight.

"Every month, [she gained] between 5 to 8 pounds. … We don't know where the weight was coming [from]," she says. "My biggest fear was mentally, Cassie would crash. She'd become depressed, she'd eat because of the depression, she'd stop sports, she'd stop being who she was."

When Cassie revealed that she was being teased about her weight, Jennifer says she decided it was time to take action. She researched gastric banding surgery and found a doctor in Mexico who agreed to perform the procedure. "In the United States, there are no other options for these children," she says. "No doctor would touch her."

Jennifer says maternal instincts made her want to fix things for her child. "You want to protect them and do what's right for them," Jennifer says. "I know this was major, but in my heart, I felt I was doing the right thing for her."
Cassie and Jennifer

At age 13, Cassie became one of the youngest patients ever to undergo a gastric banding procedure.

Unlike gastric bypass, gastric banding doesn't permanently alter the digestive system. Instead, an adjustable belt is placed around the upper part of the stomach. This belt restricts the amount of food you can eat and slows how quickly food empties from the stomach, which causes a constant feeling of fullness.

An inflatable, saline-filled tube on the inside of the belt allows doctors to squeeze the stomach tighter by filling it with extra fluid or deflate it so a patient can put on weight.

When Cassie and her mother first arrived at the Tijuana surgical clinic, they both say they felt scared. "It was the first time I ever went into Mexico," Cassie says.

"I just kept thinking, 'Is this the right decision?'" Jennifer says. "The things going through my mind were, 'She's out of my hands now. I can't protect her—and her life is in their hands.'"

Once inside the operating room, Cassie says the doctors put her at ease. Her surgery was a success, and she says she was up and walking soon after the anesthesia wore off.
Jennifer and her daughter, Cassie

Since her surgery, Cassie has dropped almost 80 pounds. Today, at 141 pounds, she says she's happier and healthier.

Her outward appearance isn't the only thing that's changed. Cassie has also developed new eating habits. "I can eat anything I want, it's just smaller portions. I can eat like a hamburger, take three bites of a hamburger and maybe two french fries, and I'm set," she says. "It's like they put a different kind of gas tank in me and whenever it hits full, you're full."

Despite the risks, Jennifer says she's glad they didn't wait until Cassie was older to have the surgery. "I didn't want her knees to go," she says. "I didn't want her to get diabetes. I didn't want it to go past the point of no return."

If she had the funds, Jennifer says she'd help other obese teens get gastric banding surgery. "I'll tell anybody, you know, this is [less] invasive. It's proven with her. She's very happy, and most of all, she's healthy."
MacGregor struggled with his weight throughout childhood.

As a child, MacGregor says he tried every diet and weight loss plan imaginable, but he continued to gain about 50 pounds a year.

At 12 years old, MacGregor's parents enrolled him in a summer weight loss camp for kids. That summer, he went from 250 to 200 pounds. When he returned home, his healthy habits came to a halt. One month later, MacGregor says he'd gained the weight back and was right back where he started.

"I figured this is what it's going to be [like] for the rest of my life … so I might as well get used to it," he says. "I was depressed, but you couldn't tell at all. I would put on a happy face and be able to run around and hang out with everybody, but still be the quiet fat kid in the corner at the same time."

Every time MacGregor looked in the mirror, he says he saw the dark shades of depression. "I wouldn't see it take over my whole face," he says. "I'd still see a smile and say, 'Well, everything's going to be all right.'"

Over time, MacGregor went from 250 to 300 pounds. When he reached 360 pounds his mother, Jacqueline, says she started to fear for his life.
Jacqueline and her son, MacGregor

Determined to help her son, Jacqueline logged onto the Internet and began researching weight loss options for children. She found a program at the University of Illinois at Chicago that was studying gastric banding surgery for teens, and she submitted MacGregor as a candidate.

Before the university would agree to perform the procedure, MacGregor had to go through six months of testing, including psychological analysis.

"They really worked very closely with the children as far as even getting them ready," Jacqueline says. "They work with you with a psychologist, with the regular doctors, nutritionists. … It just gave him a whole head start to how his life was going to be changed."
MacGregor has lost 150 pounds.

In October 2006, MacGregor had gastric banding surgery. Since then, he's lost more than 150 pounds.

At one point, his weight was down to 179 pounds, but ironically, he says his football coaches asked him to put on weight. To absorb more calories, MacGregor's doctors widened the belt that squeezes his stomach. This allowed him to consume more food. "I bulked up to about 215 throughout the season, but surprisingly enough, I still sat the bench," he says.

Though he's always been an active kid, MacGregor says he stepped up his exercise regiment when the pounds starting coming off. He says his parents also helped him lose weight by keeping low-calorie, non-fatty foods in the house.

With the band in place, MacGregor says he just can't eat the way he once did. "I couldn't really … order, like, two cheeseburgers and some fries," he says. "It would come back up."

As MacGregor's weight goes down, his self-confidence continues to go up. "I love myself more," he says. "I love looking in the mirror. I love being able to go out and buy clothes that I don't have to get specifically made for myself."

Though he says every day is a battle, he's working hard to maintain the weight loss. "You have to take it in stride," he says. "I don't know what the future is going to bring, but I hope [to keep the weight off]."
Kylie decides to undergo gastric bypass surgery.

When she was just 17 years old, Kylie began losing her eyesight as a result of her weight. This complication of obesity—known as pseudotumor cerebri—is usually only found in adult women.

At the time, Kylie weighed more than 250 pounds. She says her obesity caused spinal fluid to build up between her optic nerves and brain, causing severe migraines and eyesight loss. To avoid permanent damage, she took drastic measures.

Kylie underwent gastric bypass surgery, an irreversible operation that reduces the stomach from the size of a melon to the size of a walnut. Doctors do this by creating a tiny pouch at the top of the stomach and sealing off the rest. Then, they cut the small intestine in two and attach the lower part to the small pouch. The new stomach can only hold about six grapes.

Once the new stomach is in place, food moves quickly through the digestive system to the small intestine, which means fewer calories are absorbed.
Kylie has lost 120 pounds since her surgery.

Before having gastric bypass surgery, Kylie says she'd been dieting since she was 9 years old, but nothing seemed to work. Now, she's lost 120 pounds.

For a few weeks after the surgery, Kylie says she wasn't allowed to have solid foods. She lived on Jell-O, chicken broth and sugar-free Popsicles. These days, however, she says she can eat almost anything…in small quantities.

"Now I can eat probably maybe half a hamburger, a few fries, and I'm done," she says. If she ate more, Kylie says she'd get sick and throw up.

Though she's happy with her weight loss, she says she's having a hard time adjusting to a world without dieting. "I am dealing with a lot of psychological issues around maintaining because I've known how to lose weight for so long," she says. "Now doctors are saying, 'You don't have to drink non-fat milk. You don't have to have low fat. It's okay to have the whole milk.' It's freaking me out."
Nathaniel decided to have gastric bypass surgery.

Nathaniel is a high school senior who weighed 340 pounds. Like Kylie, he decided to have gastric bypass surgery.

"I've tried many diets," he says. "I just felt that none of them were really successful. I want to live a long, good life, and I know if I stay as I am, I know that there would be some problems."

At 340 pounds, Nathaniel says he was struggling with his health. "I'm not a full-blown diabetic, but they think I'm borderline of being type two diabetes, and that's a big concern. I have major back problems, and then with my acid reflux it'll make my chest start hurting … I'm scared to the point where I feel like I'm having a heart attack."

Nathaniel's mother, Connie, hopes the surgery will help bring an end to her son's health problems. "His health was progressively getting worse. The diabetes, the sleep apnea, it was his knees, his ankles. He really had no choice but to get the weight off, and this was the last resort."

His weight has also affected his social life. "When I was in like kindergarten through like third grade, they would always tease me, you know, 'Fat boy, blah blah blah,' and it really hurt me. I got to the point to where I didn't even want to go to school anymore. As I got older, I learned to just take what they say and I kinda turn it into a joke."
Dr. Brandt performed Nathaniel's gastric bypass surgery.

Although there are risks associated with gastric bypass surgery, the consequences of not having the surgery were weighing on Connie's mind. "How long would it have been, you know, had he not had this surgery? How long would his life span be?," she says. "I would never want to bury my child before me. There's no way I could live through that."

Surgeon Mary Brandt says Nathaniel's health problems could become life-threatening without treatment. "A lot of people view bariatric surgery as treating obesity," she says. "But for teenagers in particular, it's actually treating the consequences of the obesity. Nathaniel has the kind of co-morbidities that we think will kill him eventually if he doesn't have treatment."

Cameras followed Nathanial as he went into the operating room to undergo the irreversible procedure. From the waiting area, Connie worries about her son. "It doesn't matter how old he is, how big he is, you know. He's my baby, so I worry, but I really believe that everything's going to be fine."

After a successful operation, Nathaniel is in good spirits. "I feel good. The pain from the surgery's not that bad; I'm just sore," he says. "It's been fun."
Dr. Brandt, Nathaniel's surgeon

Nathaniel's surgeon, Dr. Brandt, is professor of pediatric surgery at Texas Children's Hospital. Just nine days after the surgery, Dr. Brandt says Nathaniel is doing great. "He's lost 14 pounds," she says. "He's going to be back to school next week." She says she expects Nathaniel will lose around 30 pounds in the first month following surgery.

Dr. Brandt says she understands the controversy surrounding teen weight loss surgery—at first, even she was opposed to it. "You know, pediatric surgeons do all the surgeries adults do, but we have to think about growth," she says. "And these children are still growing. And so I was very concerned about the consequences of this surgery."

Over time, Dr. Brandt's outlook began to change. "I actually started meeting children who weigh 500 pounds who were literally dying—couldn't go to school, couldn't sit in the chairs in school. Machines at night to help them breathe," she says.

Still, Dr. Brandt doesn't take performing the surgeries lightly. "We've set some very stringent criteria for when children should be considered for this, and the bar is much higher than adults," she says. "You really not only have to be overweight, you have to have major problems like losing your sight or having diabetes or having sleep apnea."

Dr. Brandt also has her patients attend therapy sessions prior to surgery. "We see kids for months in advance. They come to support group, they're evaluated by psychologists."
Dr. Oz

Can a child who's had gastric bypass surgery keep the weight off—especially if he's surrounded by a family with poor eating habits? Dr. Brandt says yes, because the surgery is an enforced behavioral modification. "The behavior that we're all supposed to learn if we're going to lose weight, you must do it if you've had the surgery," she says. "I think that's the key. You can't cheat."

Not all doctors agree with Dr. Brandt's methods. Dr. Diana Farmer, a pediatric surgeon at the University of California, San Francisco Children's Hospital, thinks children should wait before going under the knife. "Many people argue that this kind of surgery is worth the risk because it will save lives in the long-term," she says. "My question is, 'How many children are dropping dead from obesity before the age of 18?' The answer is none. … There are very serious long-term implications related to this surgery."

Dr. Mehmet Oz also warns that neither surgery is necessarily a permanent fix. "The stomach can grow," he says. "If the band, for example, is placed at a spot that's not ideal, it can shift. But in gastric bypass surgery, the pouch size could also grow. People can eat their way through these diets by [eating] lots of milk shakes and foods that don't have a lot of substance to them."
Kendall had gastric bypass surgery at age 16.

When we first met Kendall in 2004, she was a 17-year-old high school student who had just lost 145 pounds, thanks to gastric bypass surgery. Before the operation, she weighed 265 pounds.

At the time, Kendall was thrilled with her results. "It's just incredible," she says. "My life has done a 180. I'm just so much more happy and confident."

Kendall says that for her, surgery was a matter of life and death. "It really gave me my life back."
Kendall and Oprah

Since her surgery, Kendall says she has successfully maintained her weight loss—but hasn't been able to control other aspects of her life. "A lot has happened [since the show]," Kendall says. "I went from the addiction of food, obviously, and transferred over to alcohol."

Kendall says she began drinking in moderation at college. "Progressively, I noticed that I would be drinking more than my friends, blacking out—and that's another thing that with this surgery, alcohol affects you so much more."

Dr. Oz says this happens because, after gastric bypass surgery, alcohol will pass the stomach and go straight down to the small intestine where it is mainlined to the liver. "Even a small amount of alcohol will immediately raise your blood level of alcohol so you get drunk faster, which is why you'll black out and other things will happen," he says.

"For me, rock bottom was losing friends because of the alcoholism. I lost a couple of my best friends, and I'll never be able to get those relationships back," Kendall says. To try and make amends and move on with her life, Kendall attempted to beat her alcoholism. "I was going to [AA] meetings, I was sober for two months, I joined the local church, and life was good," she says. Her success didn't last long—Kendall says she fell back into her old habits and is once again struggling to get back in control.

Looking back, Kendall says she wishes she had gone through a program that included psychological analysis. "I had such a naive mind-set. Sixteen years old, all I was thinking was, 'I want to lose this weight. I want to be happy. I want to date.' And it was going to be the cure, and it turns out there's other things that can come from it."
Dr. Oz

Kendall's addiction transfer is a major problem—one Dr. Oz says is a reason children should consider waiting until they are adults to have weightloss surgery. "The biggest concern I have with operating on kids—and I hate to say it, but since you're not legal adults yet, that's the best term to use for you—is that you're still evolving your own coping mechanisms," he says. To help avoid a problem like Kendall's, Dr. Oz says it is absolutely essential for a program to include a great deal of follow-up to help the children deal with the emotional issues they're facing.

"We still don't know what issues will occur emotionally as kids have decisions made [for them] by moms who care about them. All the moms who are doing this, you took a lot of effort. I can tell how much pain there was for you just to have to go through this process. I know that," Dr. Oz says. "But [at] age 13, it's a big decision to make and a penalty you may pay for the rest of your life because none of these operations are without risk. Anything that's strong enough to help you is strong enough to hurt you also."

At age 14, Whitney weighed 230 pounds. A year later, she was more than 100 pounds thinner and landed in the pages of Seventeen Magazine as one of the "Best-Tressed Girls in America." How did she do it? It wasn't with a surgical solution—Whitney just took it one step at a time.

"I started by just going to my gym. … I got on the treadmill every single day, and I would walk for 30 minutes. And I eventually started running," she says. "I hated running. But I decided it was the easiest way to lose weight, so I started running. At first, I could do just three minutes. Then four. And then I just kept going up until I could run for 30 minutes without stopping."

Healthy foods were also a big part of her plan. Before, Whitney says she never counted calories. "I didn't think much about it. Hamburger, french fries every day, pizza. I ate whatever I wanted whenever I wanted." Now, Whitney says she makes the grocery list for her parents to ensure that only healthy foods fill their cabinets.

"I never would have imagined at 230 pounds that I would be here," Whitney says. "I just have gained so much confidence from it all. I mean, I'm just so happy with my decision."
Dr. Oz talks about the future of the obesity epidemic.

Dr. Oz says education is key to curbing child obesity in the future. "Instead of trying to diet hard, we've got to diet smart. If you understand the biology of blubber, it becomes easier to do it."

Dr. Brandt says she thinks the obesity epidemic is a failure of society—but one that is fixable. To demonstrate her point, she uses cigarettes as an example. "The first reaction was, 'Cigarettes aren't that bad for you'—and it took about five years before people said, 'Well, yes, it is bad for you,'" she says. After another 10, 15 years, Dr. Brandt says there was a real movement to stop smoking. "I think that's where we are with this obesity epidemic," she says. "We have announced it. They're starting to get it. And 15 years from now, I hope I'm out of business."

In the end, Dr. Oz says the children are the key to change. "You're going to go back into our homes, into our communities, you're going to be the activists that will change this entire equation, and it will be you who drive this whole movement."

Healthy ways to control your weight