The Community Preventive Services Task Force, an independent, unpaid group of public health and prevention experts who develop recommendations for community health, commissioned a review of 53 studies describing 66 combined diet and physical activity promotion programmes. The studies were done between 1991 and 2015.
Counselling, coaching and support
The Task Force found strong evidence that these programmes are effective at reducing the number of new cases of diabetes, according to a report in Annals of Internal Medicine.
"If you exercise and eat better, you'll reduce your risk of developing diabetes," said Dr Patrick L Remington, co-author of the recommendation statement on behalf of the Task Force. "But if you simply tell somebody to eat better and exercise, that does not work."
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The diet and exercise promotion programmes included providers or trained laypeople working directly with participants for at least three months, providing counselling, coaching and support over multiple sessions.
Some also included specialists like nutritionists, physiotherapists, individually tailored diet and exercise programmes and specific weight-loss goals.
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The programmes were targeted to teens and adults with "pre-diabetes", marked by elevated blood sugar levels that were not yet high enough to be diagnosed with type 2 diabetes.
"In general, people who may be at increased risk for diabetes (both adults and children) include those who are overweight or obese and those who have a sedentary lifestyle," Dr Ethan Balk of Brown University in Providence, Rhode Island, lead author of the evidence review, told Reuters Health by email.
The review found that community-based programmes helped improve weight loss, lower blood sugar and reduce the risk for a later diabetes diagnosis. Some also reduced blood sugar and improved cholesterol markers, and none reported any long-term harms related to the programmes.
Many years of healthy life
In an economic assessment, the Task Force also found that these programmes are cost-effective. Half of participants paid less than $653 (±R8,300) to take part, and costs were lower for group-based or primary-care based programmes.
"This is more cost effective than most of what we do in medicine, but not cost saving, it does cost something," Remington said by phone. "But the return for those costs are many years of healthy life gained, so we consider it cost effective."
Gyms and health clubs already offer these types of programmes for a modest fee, he said.
"It's shocking," he added, "that we are not doing it as a routine part of the health care system. We've designed a healthcare system to treat sick people, not to prevent disease."
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The first step may be a change in providers' attitudes, he said, noting that many doctors do not believe that diabetes can be prevented through lifestyle changes.
'Find a programme near you'
"I think that the medical community has been so influenced by long term secular trends that they've lost confidence in the individual to treat themselves through lifestyle changes," he said.
Then the insurance and outreach system needs to change, and training laypeople or non-physician specialists to provide these programmes should increase, he said.
"The (Affordable Care Act) doesn't really cover these type of intense prevention programmes," Remington said. "Generally we've left people alone with advice."
There are National Diabetes Prevention Programme resources in every state, and the Centres for Disease Control and Prevention has a registry of recognised programmes and a "Find a programme near you" function.
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