What happens in Room 6 at the Y.M.C.A. in Wayne, N.J., on Wednesday mornings doesn’t look terribly dramatic. About a dozen people trickle in, step on a digital scale, show the program leader Elizabeth Youngstein their logs — on iPads or smartphones or in paper notebooks — recording what they ate since last week and how much they exercised.
“We want 150 minutes per week,” Ms. Youngstein said. “So I track whether they’ve tracked.”
Then, as in any support group, members sit around a table and talk about what worked this week and what didn’t. Barbara Biazzo knows she’s not drinking enough water, “but at least I’m moving.” Marilyn Gerardi enjoys using the treadmill, but it hurts her knees; Ms. Youngstein suggests a recumbent bike. Joe Venezia is substituting Greek yogurt with horseradish for mayonnaise.
Most participants here are in their late 50s and 60s, but Rosalie Scudellari is 84. “I somehow see your face when I think about another snack,” she tells Ms. Youngstein.
It’s Week 5 of the Diabetes Prevention Program, and however commonplace the conversation, the results can be impressive. In 2002, a large national clinical trial showed that among adults at risk for Type 2 diabetes, this “lifestyle modification program” and resulting weight loss reduced the incidence of the disease by 58 percent in 1,000 subjects participating in the program, compared with those who did not — and by an even more substantial 71 percent in those over age 60.
So the Centers for Disease Control and Prevention began rolling out the National Diabetes Prevention Program in 2012. Now, 527 organizations around the country — health care providers, community groups, employers, colleges, churches — offer it in every state, often at multiple sites. Several providers are experimenting with online versions. The Y.M.C.A., the largest single organization involved, enrolls 40 percent of participants nationally.
This may be the largest national health effort that most of us haven’t heard of, and one of the most important, especially for older adults.
Ann Albright, who directs the diabetes division at the C.D.C., estimates that in the first two years nearly 50,000 Americans have joined one of its recognized diabetes prevention programs, which are aimed at people whose weight, blood glucose levels or other factors suggest they are at elevated risk for developing the disease.
“This is not a ‘diet,’ some sort of temporary thing,” Dr. Albright said. “This is intended to help people adopt new habits and to look at that as a way of life.”
The C.D.C. curriculum involves 16 weekly sessions, then monthly follow-ups for a year. The goal, along with 150 minutes a week of walking or other physical activity, is significant weight loss. “You will get diabetes reduction at 4 percent” of body weight, Dr. Albright said. “But we’re shooting for 5 to 7 percent.” In Y.M.C.A. programs, the organization says, participants average a 5.7 percent loss after a year.
Why do older people do particularly well in this program? “It probably has to do with their commitment,” Dr. Albright said. “They become more engaged. Maybe they realize where they are in their life course.”
And maybe they see more diabetes, with its pernicious effects. Close to 10 percent of the population in the United States has Type 2 diabetes, diagnosed or undiagnosed, Dr. Albright pointed out. But prevalence rises with age: Among those over age 65, nearly 26 percent have the disease.
“We’ve got the evidence. We know what to do,” Dr. Albright said. “Are we going to make it work?”
The C.D.C. and other public health advocates face two considerable barriers. First, though the number of groups with C.D.C.-recognized diabetes prevention programs keeps growing, it remains insufficient. About 86 million Americans are prediabetic, the agency estimates. Compared with that, 50,000 program participants sounds “pretty wimpy,” Dr. Albright acknowledged. “We need millions” — a major public awareness challenge.
Second, the program’s cost, while lower than some gym memberships, could discourage people, particularly seniors. The C.D.C. estimates that the yearlong intervention costs an average $ 500 to provide. Each organization sets its own charges; at the Y, the sticker price is $ 429 for the year. (Here’s a list of participating Y.M.C.A.s.)
Groups work to lower costs with fund-raising, grants and scholarships (the Wayne Y.M.C.A. program was free because of a pharmaceutical firm grant), and some insurers cover the program. But Medicare and Medicaid don’t.
The C.D.C. is pushing for Medicare coverage; legislation to mandate Medicare coverage has also been introduced in the House and the Senate. Dr. Albright sounded optimistic. “It’s more expensive to treat diabetes,” she said, than to prevent it.
Increased exercise and healthier eating, the program’s central tenets, have become so broadly understood that you might wonder why sitting in a room with a dozen others helps people achieve them. But research shows that it does.
“They hear what other people are going through and think, ‘If they can do it, I can do it,’ ” Ms. Youngstein said of her group.
It has worked that way for Walter Weiss, a retired postal worker with a family history of diabetes. “My doctors want me to lose weight,” he told me after the meeting. “Every time I go: ‘Lose weight.’ ” His children were concerned enough to buy him a Fitbit last Christmas.
A healthier lifestyle always seemed too difficult, but he has turned 69, and “the older you get, the more you contemplate your mortality,” Mr. Weiss said. He weighed 243 pounds when he began the program in November and has lost nine pounds to date. Using the 7 percent goal, he has eight pounds to go.
Mr. Weiss showed me his meticulous tracking in a spiral notebook, noting every egg-white mushroom omelet and roasted chickpea snack, every exercise session. The latter have expanded.
Walking through his condo complex proved a bit boring, he said, so he does a daily two-mile loop around a park reservoir, instead.
“Some days,” he said, “I feel good and I go around again.”