"He's continuously hungry," said Denzel's mother Patti Jones. "He says it feels like knives are cutting his stomach when he gets hungry."
But Denzel has been on an 800 calorie a day diet for months. It's been extremely hard.
He said, "Every day we prayed God was right there with me."
He's lost about 150 pounds, and he's still dieting.
"I'm still working on a little more," Denzel said. "I want to get to 200."
Denzel's doctor also prescribed a breathing machine to help with his sleep apnea. But sleeping longer and better can also help control his hunger.
"We're just learning how important sleep is for managing our weight," said Dr. Josh Rotenberg. "It affects hormones that affect satiety, that affect hunger and affect how full you are."
A University of Washington study found infants and children who don't get enough sleep may be more likely to be obese before adulthood.
Dr. Rotenberg said, "The less you sleep, the more hungry you feel, the more carbs in your diet and over time that translates into weight gain."
How much sleep do children need?
How do you know if your child has a sleep problem? Dr. Rotenberg says watch for irritability, sleepiness in the day, snoring, and sleeping extremely late on the weekends. Dr. Rotenberg says the message is simple.
"Eat less, move more, sleep more," he said.
Getting a good night's sleep is one more way parents can help their children avoid obesity.