Could a drizzle of olive oil, a brisk walk, and smaller portions help stop type-2 diabetes before it starts? A six-year Spanish clinical trial suggests the answer may be yes for adults who already carry several warning signs.
The PREDIMED-Plus diabetes analysis followed 4,746 adults and found that a calorie-reduced Mediterranean diet, regular exercise, and professional support worked better than Mediterranean diet advice alone. The important point is the package, not one miracle menu.
What PREDIMED-Plus tested
The 23-center trial enrolled adults ages 55 to 75 overweight or with obesity, no diabetes or cardiovascular disease, and metabolic syndrome. That syndrome is a cluster of warning signs that can include a larger waist, high blood pressure, unhealthy blood fats, and elevated fasting blood sugar.
Researchers randomly assigned them to two groups. One group aimed to eat about 600 fewer calories daily, follow a Mediterranean diet, do brisk walking plus strength and balance exercises, and attend weight-loss counseling.
The comparison group received Mediterranean diet advice without a calorie target or organized exercise plan.
A clear but modest benefit
After about six years, 280 people in the intervention group developed type-2 diabetes, compared with 349 in the comparison group. That worked out to 9.5% versus 12%. The 31% figure refers to the adjusted relative rate over time, while the absolute six-year gap was about 2.5 diagnoses per 100 participants.
The intervention group lost an average of 7.3 lbs. and trimmed about 1.4” from the waist. The comparison group lost about 1.3 lbs. and roughly 1/10th of an inch. The changes were modest, but they held up over years rather than weeks.
Why waist size matters
A shrinking waist is not only about how clothes fit. Visceral fat sits deep around internal organs, where it can release substances that promote inflammation and interfere with the body’s response to insulin.
Insulin helps move sugar from the blood into cells for energy. When cells stop responding normally, the pancreas works harder, blood sugar rises, and type-2 diabetes can follow.
Food and movement worked together
The Mediterranean pattern emphasizes vegetables, beans, whole grains, fish, nuts, and olive oil while limiting highly processed foods and oversized portions. Exercise adds another route to better blood sugar control because working muscles can use more glucose.
First author Miguel Ruiz-Canela, working with principal investigator Miguel Ángel Martínez-González at the University of Navarra, said, “The Mediterranean diet acts synergistically to improve insulin sensitivity and reduce inflammation.”
Put simply, the food pattern, calorie cut, walking, strength work, and coaching supported one another.
Olive oil is not a magic shield
It would be a mistake to read the trial as proof that olive oil alone prevents diabetes. Extra-virgin olive oil keeps more naturally occurring plant compounds than refined oil, but it remains calorie-dense and works best within an overall eating pattern.
The earlier PREDIMED trial found fewer major cardiovascular events among high-risk adults assigned a Mediterranean diet supplemented with extra-virgin olive oil or nuts.
A newer analysis found stronger cardiovascular associations for extra-virgin oil than for common olive oil, although it could not prove cause and effect.
Earlier research explains the result
A three-year analysis of 1,521 participants found that the same program reduced total and visceral fat while slowing age-related loss of lean mass. That matters because muscle helps the body handle glucose, and losing weight without giving up too much muscle is difficult for many older adults.
The new diabetes finding fits that picture. Less deep abdominal fat, more movement, and better diet quality can all push metabolism in a healthier direction, even with modest weight loss.
The result has limits
The findings came from older adults in Spain with excess weight and metabolic syndrome, so they may not apply equally to younger, leaner, or lower-risk people. Diabetes was a planned secondary outcome, and dietary adherence was self-reported.
The study also cannot separate the effects of eating less, exercising, improving food quality, losing weight, and receiving support. What succeeded was the complete program–not one simple hack.
Diabetes keeps spreading
The IDF Diabetes Atlas estimates that 589 million adults ages 20 to 79 were living with diabetes worldwide in 2024, with 853 million projected by 2050. In the United States, the CDC estimates that 40.1 million people had diagnosed or undiagnosed diabetes in 2023.
Copying the Spanish program is not as simple as handing everyone olive oil and walking shoes, though.
In an Annals commentary, Sharon Herring and Gina Tripicchio of Temple University warned that food prices, unsafe streets, and limited counseling can block healthy choices. An olive oil bottle cannot replace an affordable grocery store or a safe sidewalk.
What this means in practice
PREDIMED-Plus tested a structured program, not a crash diet. In practical terms, it means better food quality, smaller portions, brisk movement, strength work, and steady guidance, but cutting 600 calories should not become a universal prescription without medical advice.
At the end of the day, modest changes mattered because people sustained them.
The main study has been published in Annals of Internal Medicine.
