They say you are what you eat, but the things you do matter for your health just as much as your diet.
Eating well and staying active are hardly new ideas, but a new study tracking thousands of people for more than two decades has put some serious weight behind just how much these habits actually matter. The findings suggest that making lifestyle changes in middle age can reduce the risk of developing multiple serious illnesses well into old age.
Where this research came from
The study draws on data from the Diabetes Prevention Program and its long-running follow-up study, which together tracked participants for over 20 years. Researchers from institutions across the US analysed the health records of 1,173 people who had originally joined the programme with prediabetes, a condition where blood sugar is higher than normal but not yet high enough to be diagnosed as full diabetes.
Participants were split into three groups at the start: one taking a daily placebo, one taking the diabetes medication metformin, and one placed on a structured diet and exercise plan aimed at losing at least 7% of their body weight. These routines were followed for three years before the longer observation period began.
The results were extremely clear.
Over more than two decades of follow-up, the group that had followed the diet and exercise plan was much less likely to develop combinations of serious illnesses, things like heart failure and dementia appearing together. This is what researchers refer to as multimorbidity, which simply means having two or more chronic conditions at the same time.
The lifestyle group had a 21% lower risk of developing multimorbidity compared with those who had been on the placebo. Crucially, even when diabetes was removed from the equation entirely, the overall reduction in chronic disease risk held up, showing the benefits stretched well beyond the original focus of the research.
How the medication group compared
The metformin group, which continued taking the medication into the follow-up study, showed very little difference in chronic disease outcomes compared with the original placebo group. This means that while metformin is genuinely useful for managing blood sugar, it didn’t appear to offer the same broad protective effect against multiple conditions that lifestyle changes did.
This distinction matters because it suggests that medication alone, however effective for its intended purpose, can’t replicate what years of consistent healthy habits actually do for the body over the long term.
Which conditions were included in the study?
Researchers tracked 15 different chronic conditions across all participants over the study period. These included high blood pressure, heart failure, coronary artery disease, cardiac arrhythmias, high cholesterol, stroke, arthritis, asthma, cancer, chronic kidney disease, chronic obstructive pulmonary disease, dementia including Alzheimer’s, depression, osteoporosis, and diabetes.
The breadth of this list is part of what makes the findings so important, since it wasn’t just one or two conditions being monitored, but a wide range of serious health problems that affect millions of people as they age.
The findings are significant beyond diabetes.
A medical officer at the National Institute on Aging, pointed out that while preventing diabetes is critically important, preventing the build-up of multiple chronic diseases as people get older has even broader implications for quality of life, independence, and healthcare costs. In other words, the goal isn’t just avoiding one illness, it’s reaching old age in genuinely good health rather than simply living longer.
An epidemiologist at the Colorado School of Public Health, added that the findings highlight the long-term value of healthy eating, regular physical activity, and managing body weight. These aren’t complicated medical interventions, they’re things most people can work towards without needing specialist help or expensive treatments.
The less encouraging side of the numbers can’t be ignored.
Despite the positive headline result, the study also contained a sobering statistic worth knowing. Across all participants, including those who had followed the diet and exercise programme, 85% still developed at least two chronic conditions over the course of the study.
This serves as a reminder that healthy habits reduce risk rather than eliminate it entirely, and that ageing itself remains a powerful factor regardless of lifestyle. As the global population gets older, there’s a growing recognition that simply living longer doesn’t automatically mean living well.
So, what does this mean for overall health?
The assistant dean at the Colorado School of Public Health, said the findings offer a clear reminder that investments in prevention genuinely matter, both for individuals and for the healthcare systems trying to manage rising rates of chronic illness. Every person who avoids developing multiple serious conditions represents not just a better quality of life but a real reduction in the burden on health services.
While the study shows a strong association between lifestyle and health outcomes rather than definitive proof of cause and effect, the pattern held firm across more than two decades of observation and was adjusted for factors like age, sex, alcohol consumption, and body mass index, making the link about as robust as this kind of long-term research can realistically get.
