Spanish study finds 31% diabetes reduction

Spanish researchers said a six-year lifestyle intervention built around a calorie-reduced Mediterranean diet, physical activity and weight-loss counseling lowered the incidence of type 2 diabetes in older adults at high cardiometabolic risk. The finding comes from PREDIMED-Plus, a large Spanish randomized trial that followed 4,746 adults ages 55 to 75 with overweight or obesity and metabolic syndrome, but no diabetes or cardiovascular disease at baseline. The results were published in *Annals of Internal Medicine* and highlighted again on May 19 in a research release from the University of Navarra. The intervention group was 31% less likely to develop type 2 diabetes than participants advised to follow a traditional Mediterranean diet without calorie restriction or exercise guidance. ### Who was in the study, and what were researchers testing? The trial enrolled 4,746 adults in Spain between 2014 and 2016 and followed them for a median of six years. All participants were 55 to 75 years old, had overweight or obesity and metabolic syndrome, and did not have diabetes or cardiovascular disease when the study began. The work was carried out at more than 100 primary care centers in Spain’s National Health System, according to the University of Navarra release. (sciencedaily.com) Researchers compared two approaches. One group received an energy-reduced Mediterranean diet with a planned reduction of about 600 kilocalories per day, moderate physical activity and behavioral support for weight loss. The control group was advised to follow an ad libitum Mediterranean diet, meaning Mediterranean-style eating without the added calorie target, exercise program or structured weight-loss support. (sciencedaily.com) ### How large was the diabetes effect? The study reported a 31% relative reduction in diabetes incidence in the intervention group compared with the control group. According to the study abstract, the six-year absolute risk was 9.5% in the intervention group, with 280 cases, versus 12.0% in the control group, with 349 cases. The absolute risk reduction was 2.6 cases per 1,000 person-years, the abstract said. (sciencedaily.com) Frank Hu of Harvard T.H. Chan School of Public Health, a co-author, said in a school release issued when the paper was published that the findings offered “highest-level evidence” that modest, sustained changes in diet and lifestyle could help prevent type 2 diabetes. The Harvard release described the study as showing that a Mediterranean-style diet paired with reduced caloric intake, moderate physical activity and professional support for weight loss cut diabetes risk by nearly one-third. (ramao.es) ### What exactly did the intervention ask people to do? The intervention combined three elements: lower calorie intake, moderate exercise and coaching. The University of Navarra release said participants were asked to follow a Mediterranean-style diet with roughly 600 fewer kilocalories per day, and to add brisk walking, strength training and balance exercises. They also received professional guidance aimed at weight management and long-term adherence. (hsph.harvard.edu) The control group was not told to abandon the Mediterranean diet. Instead, participants were advised to follow a standard Mediterranean pattern without the same calorie restriction or structured physical-activity plan. That distinction matters because the trial tested an intensified version of Mediterranean-style living against Mediterranean advice alone, rather than against a Western diet. (sciencedaily.com) ### Did the study show anything beyond diabetes incidence? A related PREDIMED-Plus analysis published earlier in *JAMA Network Open* found that the intervention reduced total and visceral fat and attenuated loss of lean mass over three years in older adults with overweight or obesity and metabolic syndrome. That analysis involved 1,521 participants and examined body-composition changes rather than diabetes incidence. (sciencedaily.com) The May 19 research release also said participants in the more intensive program lost more weight and reduced waist size compared with those assigned to the standard Mediterranean-diet approach. Those findings were presented alongside the diabetes result in the university summary of the six-year follow-up. ### Where does this leave the evidence? (jamanetwork.com) The paper was published in *Annals of Internal Medicine* on August 26, 2025, under the title “Comparison of an Energy-Reduced Mediterranean Diet and Physical Activity Versus an Ad Libitum Mediterranean Diet in the Prevention of Type 2 Diabetes.” The study was funded through a mix of Spanish public research support and an earlier European Research Council grant, according to the University of Navarra release. (sciencedaily.com) The next reference point for readers is the journal article itself and related follow-up analyses from the PREDIMED-Plus investigators, including prior body-composition work in *JAMA Network Open*. The named participants in the project include researchers from the University of Navarra, CIBEROBN, CIBERESP, CIBERDEM and Harvard T.H. Chan School of Public Health. (nature.com)