Losing weight in middle age could reduce chronic diseases later, study shows

CNN

27-05-2025

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All the work that goes into losing weight in middle age could set you up for a longer, healthier life later, according to a new study.
A sustained weight loss of about 6.5% of body weight without medications or surgery in middle-aged people is linked to substantial long-term health benefits, said lead study author Dr. Timo Strandberg, professor of geriatric medicine at the University of Helsinki in Finland.
Those benefits included a reduction of risk for both chronic diseases and death from all causes.
The study, published Tuesday in the journal JAMA Network Open, analyzed data of about 23,000 people from three different groups across different time periods: one group from 1985 to 1988, another from 1964 to 1973, and a third between 2000 and 2013.
Researchers grouped the people in the studies based on their starting body mass index (BMI) and whether they gained, lost or maintained weight and compared the patterns with hospitalizations and death records.
People who lost weight in midlife were less likely to experience heart attacks, strokes, cancer, asthma or chronic obstructive pulmonary disease in their older years, according to the study.
Those who lost weight were also less likely to have died of any cause over the next 35 years, the study found.
It's important to note that much of the data was collected before weight loss medications or surgeries were widely available, meaning that the benefits largely came from body changes driven by alterations in diet and exercise, Strandberg said.
The study is important because it provides evidence of the relationship between weight loss and both cardiovascular disease and mortality, which hasn't been studied enough, said Dr. Aayush Visaria, a clinical researcher and incoming instructor of medicine at Rutgers Robert Wood Johnson Medical School in New Jersey. He was not involved in the research.
Although the study is strong in that it utilizes a large sample, there are some limitations when applying the results, Visaria said.
The study was conducted on White Europeans, meaning that it's difficult to generalize the results to different populations, Strandberg said.
'BMI is very different across different racial ethnic groups,' Visaria said.
And BMI, which looks at weight in proportion to height, isn't always the most accurate way to gauge body composition, he added. BMI is still used widely because it is easy to calculate, but it doesn't differentiate based on a person's proportion of bone or muscle, Visaria said.
'There's so many variables that might play into how someone's body composition changes, even though maybe their weight might not change as much,' Visaria said.
Other studies suggest that the fat distribution makes a big difference –– the fat around a person's organs may be what really drives a lot of disease risk, he said.
Lifestyle changes –– such as a healthy diet and more exercise –– were important factors in the risk reduction.
The study was observational, meaning that the data can show a relationship between weight loss and a reduction in chronic disease and mortality risk, but researchers can't say for sure that the weight loss was the factor that lowered the risk, Visaria said.
Although the researchers adjusted for other factors that could influence the risk, such as age, they did not adjust for lifestyle behaviors such as diet and physical activity, he added. Those changes could be behind the lowered risk of chronic diseases just as the weight loss itself could be, Visaria said.
Both weight loss and the behavioral changes behind it are often tied together in improving health, Strandberg noted.
Weight loss relieves conditions such as osteoarthritis, obstructive sleep apnea and fatty liver, while changes to diet and exercise have been shown to decrease cardiovascular risks, he added.
Lifestyle is always important when it comes to good health, meaning that you should continue to strive for a healthy diet and good physical activity –– even if you are using weight loss medications, Visaria said.
The Mediterranean diet –– which prioritizes fruits, vegetables, grains, olive oil, and nuts and seeds –– has consistently been ranked the best diet for wellness and disease prevention.
Studies suggest this way of eating may improve bone density in older years, prevent some cancers and lower risk of heart disease.
For physical activity, the World Health Organization recommends that adults engage in at least 150 minutes per week of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity, along with muscle-strengthening activities at least twice a week.
However, obesity is not just a problem individuals need to tackle –– it is a structural issue as well, Strandberg said.
Healthy foods and opportunities for physical activity need to be more accessible in modern societies to help curb the health impacts associated with obesity, he added.