At 177 pounds, Meg Evans of San Diego, Calif., now has enough agility to play goalie for her amateur soccer team. Evans, a 60-year-old mother of four, had been an athlete all her life, but packed on the pounds as years went on, peaking at 232 pounds.
"I never ate wisely. I love my food. I love to cook. That's me," she said. "The Jenny Craig diet was a good one and I lost the weight, but...it was too late. I was already putting it back on."
Then, a couple of years ago when her blood pressure shot up, Evans said she had to find a solution. She applied and was admitted as a patient in a blind testing for a new drug called Qnexa -- one of a new class of weight-loss drugs in development.
In the same test group was 42-year-old Chris Dickerson, who had grown up as the pudgy kid, and became dangerously fat as a grown man.
"My grandmother is from Arkansas. She taught my mother how to cook. You know, fried taters, pies, cakes. You name it, she learned how to cook it," Dickerson said.
Overweight his entire life, Dickerson had difficulty even throwing a ball with his sons. "I was tired. I had no energy," he said.
With high blood pressure and fear of developing diabetes, he too, felt compelled to enroll in the Qnexa study.
Doctors and those in the drug industry have high hopes for the new medications. Qnexa is a combination of the appetite suppressant phentermine and an epilepsy drug that makes the patient feel fuller. Another drug in development, Contrave, combines an appetite suppressant and a second drug that speeds weight loss. And Lorcaserin is an entirely new medicine designed to switch off appetite in the brain and maintain metabolism.
"Obesity is a chronic disease and we need to think about chronic medication for it," said Dr. Michelle Look, a family practitioner in the San Diego area, who administered the drug trial.
At first, Evans and Dickerson said they didn't feel much of anything when they began taking Qnexa.
"I really thought I was on the placebo for a long time because I didn't have any side effects," Evans said. "I did finally realize that I didn't have any hunger pains."
"It gives you that full feeling instead of, 'hey, you got to clean your plate every time,'" Dickerson told "Nightline."
Approximately two thirds of the American population is overweight and a third is actually obese. No matter what you weigh, experts say the body has mechanisms to prevent weight loss, which go back to the days in nature when food was scarce and you had to chase it.
While diets can produce short-term loss, most people put it all back on.
"If we took your weight up 100 pounds and you lost just 15 or 20 pounds after that, your body would stop the weight loss. It would lower the metabolism. It would make you think about food," said Dr. Ken Fujioka, an obesity specialist. "That's really hard to beat. So using medications to get beyond that is really where we are headed right now."
Most diet drugs have not worked very well and some have been dangerous failures. Twelve years ago, an anti-obesity drug known as Fen-phen was taken off the market because it was shown to cause heart disease. Two years ago, another drug failed FDA approval because it led to depression and suicidal tendencies.
Phentermine from Fen-phen makes up half of Qnexa. The company claims that it's the non-"toxic" half of Fen-phen that's included in the new drug.