Oct. 11, 2010 (San Diego) -- Calorie restriction and physical activity can help overweight, obese, and even severely obese people lose weight, according to new research presented at the annual meeting of the Obesity Society.
"These interventions can work," researcher Bret H. Goodpaster, PhD, of the University of Pittsburgh, told meeting participants. "They don't always work, but they can work."
Goodpaster says he isn't suggesting that lifestyle interventions can replace weight loss surgery, but simply that they shouldn't be ruled out as an effective strategy.
In another study presented at the meeting, overweight and obese women enrolled in a structured commercial weight loss program, Jenny Craig, lost more weight than those not in the program, says researcher Cheryl L. Rock, PhD, RD, a professor of family and preventive medicine at the University of California, San Diego.
"It works," Rock tells WebMD. "No drugs, no devices, no surgery."
Both studies were published online Saturday in TheJournal of the American Medical Association.
The research drew praise and caveats, with some experts saying the findings are cause for optimism and others saying the structured program results represent a ''best-case" scenario.
Lifestyle Interventions for Severe Obesity: What Works?
More than 14% of U.S. adults are severely obese, with a body mass index (BMI) of 35 or more. But just 1% of severely obese patients get bariatric surgery each year, according to Goodpaster.
While many experts view lifestyle approaches as ineffective for the severely obese, little research has yet been done, according to Goodpaster.
In the study, Goodpaster assigned 130 severely obese adults with an average age of 46 and all with a BMI of 35 or above into two groups. Both groups were told to reduce fat and calories and given liquid and prepackaged meal replacements for free, with meal replacements tapering off as the study progressed. Small financial rewards were given for reaching goals. Support was given in group and individual meetings and by phone.
One group began exercising at the start by walking briskly five days a week, working up to 60 minutes a session. The second group began to exercise at the six-month mark.
At six months, weight loss in the group that began diet and exercise at the start was about 6 pounds higher -- 24 pounds compared to 18. But the delayed exercise group caught up.
After 12 months, 101 participants remained. "At 12 months there were no significant differences between groups in weight loss," Goodpaster says. The diet and exercise group lost about 27 pounds, while the delayed exercise group lost 22. The average BMI declined from about 44 to 39.
Both groups also had reductions in waist circumference and abdominal fat. They had improvement in insulin resistance, reducing their diabetes risk, he found.