WASHINGTON -- Community-based weight-loss programs have not been shown to be effective at reducing the incidence of diabetes, so implementing a national program would likely be money down the drain, a diabetes expert said at a symposium on Tuesday.
Richard Kahn, PhD, who was the chief scientific and medical officer of the American Diabetes Association for nearly 25 years, delivered remarks to public health advocates and diabetes researchers at the Health Affairs briefing Tuesday, where his remarks stood in stark contrast to the "prevention works" message of the event's other speakers.
He told those in attendance -- some of whom are involved in community-based weight-loss interventions -- that "community programs are ineffective at achieving weight loss."
Kahn -- who now teaches medicine at the University of North Carolina at Chapel Hill -- said that just sustaining significant weight loss, even with intensive dieting, exercise, and coaching, "requires near-heroic measures" in the face of a "very hostile food environment."
He outlined his views in a paper published in the January edition of Health Affairs, in which he wrote that there are two ways to dramatically reduce the toll of diabetes: One is to detect diabetes early and then treat it so effectively that complications from the disease are practically zero. The other is to prevent diabetes before it even happens.
Thousands of public health campaigns are aimed at prevention, and for diabetes, that generally means losing weight. But people have the "fundamental problem" of not being able to maintain weight loss, so preventing diabetes in a person at high risk for the disease is extremely difficult, Kahn said.
His paper looked at diabetes prevention studies, including the large Diabetes Prevention Program, in which patients lost an average of between 4% and 6% of their body weight (but gained about 40% back by the end of the nearly three-year trial). It also looked at the government-funded Look AHEAD trial, which found that intensive lifestyle changes resulted in a major reduction in cardiovascular risk factors, but the effects greatly diminished after four years when many participants gained weight and lost their improved fitness.
Kahn said those studies, along with the Finnish Diabetes Prevention Study -- in which the greatest diabetes prevention benefit occurred in people who lost at least 5% of their body weight -- suggest that "without substantial, sustained weight loss, progression to diabetes will probably resume." Progression to diabetes may be delayed for a few years, but the long-term effects are uncertain, he said.
(However, a preliminary study presented at the American Diabetes Association meeting last year found that a short-term lifestyle modification program for overweight diabetic patients showed long-term benefits for many of the participants.)
"In sum, to date, we have not seen a demonstration of any program that results in a clinically meaningful weight loss that can be maintained for more than two to three years in the great majority of participants and at a low cost," Kahn wrote.
Kahn's remarks preceded those of Kenneth Thorpe, of Emory University, who outlined how the healthcare reform law laid the groundwork for a national, community-based diabetes prevention strategy modeled on the Diabetes Prevention Program.
Kahn said that would be a waste of money.
"The main argument is that implementing a nationwide community intervention program is not going to do anything, I believe, except waste resources," Kahn told 鶹ý.
Kahn said that there are too many unanswered questions about how weight loss works that must be answered before a national program would ever succeed in preventing diabetes in the long term.
"We really need to know what is going on with this complex system we have," he said. "What is going on in our physiology that precludes us from losing weight and keeping it off?"
Another issue that prevents people from keeping weight off is the ubiquity of the "cheap, widely available, delicious food that we eat again and again."
He suggested "painful policies" as the solution -- such as raising the price of all food except for fruits and vegetables, and offering financial incentives to people who can keep weight off, while penalizing overweight people with higher insurance premiums.
He acknowledged those aggressive policies likely would be unpopular among members of Congress and doctors.
"While we wait for the time when lifestyle modification becomes practical, we might be better served by focusing more attention on improving our understanding of the processes that affect energy intake and expenditure and improving the medical management of diabetes," Kahn wrote.
Those medical management strategies include making an early diagnosis and administering "proven treatments that have been shown to reduce complications of diabetes and extend life," he said.
He added that the best doctors can offer right now is to suggest to overweight patients that losing 4% body weight and keeping it off can reduce the risk for serious complications of diabetes by 15% to 20%.