David Smith was born in Phoenix and grew up as a regular kid. He was active in sports and played on the swings. When he was around 7 years old, David's parents noticed that he stopped all of those activities and seemed to be depressed. He would stay inside the house and eat.

David revealed that at a very young age he was abused by the first friend he ever made. "It made me shy away from people and not trust them at all. I turned to food because it made me happy," he said.

Gaining more weight all the time and lacking social skills, David found school to be a nightmare. "I've had sticks and stones and dog feces thrown at me," David said. "I've been spit on, had a broken arm and black eyes." The emotional and physical abuse took its toll and David dropped out of high school at 17.

At age 24 David tipped the scales at 630 pounds. He was eating himself to death. After a gallbladder surgery, doctors warned David that he would die within four years if he didn't lose the weight. David was so ashamed of his weight that he thought about killing himself in a gruesome way. "I felt like I deserved as much pain as possible if I was to kill myself," he said. "To burn myself literally in the desert."

David believes he had an angel. "My mom was always telling me to lose the weight, even on her deathbed, but I couldn't make that commitment," says David. "And then the craziest thing is, the anniversary of her death was the, the day me and Chris first made contact. So that's like a sign right there."

Chris Powell was a fitness expert on Good Morning Arizona when David Smith reached out to him for help in losing 400 pounds. "We were both probably thinking what are we getting ourselves into right here," said Smith. "I thought there would be no way I'd have anything in common with this guy."

Chris devised a carb-cycling meal plan for David and started an exercise regimen. He lost 40 pounds in the first month, with no surgery or weight loss pills. Here David is 490 pounds.

After David lost such a tremendous amount of weight, he had so much excess skin that his stomach resembled a deflated balloon.

David had to undergo two surgeries to remove 23 pounds of flesh. But that wasn't his only procedure. He got Lasik surgery for his eyes, cheek implants and cosmetic dental work so he could finally do something he had never done ... step out onto the social scene.

David Smith and Chris Powell spent so much time together they eventually became best friends, even sharing a bachelor pad. "I was with him through his transformation, but he's been with me through my own journey and that's the real reason why we're so close," said Powell.

"David is the most genuine person you'll ever meet. He's got a heart of gold," said trainer Chris Powell.

David Smith says he's still a work in progress, but believes the best way to thank trainer Chris Powell is to give back. He is now a personal trainer. "If somebody was in my shoes a few years ago I would just tell them not to give up, not to lose sight of what they really want in life."