# The Mediterranean Diet Trial That Measured Heart Attacks, Not Weight

By Ruth Calder, Enforcement Editor (https://glpwatchdog.org/authors/ruth-calder) | Published: 2026-08-21 | Updated: 2026-10-27

Canonical page: https://glpwatchdog.org/research/mediterranean-diet-the-outcome-trial

> CORDIOPREV randomized 1,002 people with coronary heart disease to a Mediterranean or low-fat diet for seven years and counted cardiovascular events: 87 against 111. The benefit was clear in men and undetected among the 175 women.

## Key points

- CORDIOPREV: 1,002 patients with established coronary heart disease, randomized, 7-year follow-up, hard clinical endpoints.
- 87 primary endpoint events on the Mediterranean diet against 111 on low-fat; 28.1 vs 37.7 per 1,000 person-years.
- In men the multiadjusted hazard ratio was 0.669. Among the 175 women, no difference was found between diets.
- Secondary prevention only, and not a weight-loss trial: the endpoint was cardiovascular events.

Most diet research measures weight, or a number in blood. CORDIOPREV measured heart attacks. One thousand and two people with established coronary heart disease were randomized to a Mediterranean diet or a low-fat diet and followed for seven years, with the endpoint a composite of myocardial infarction, revascularization, ischemic stroke, peripheral artery disease and cardiovascular death. The Mediterranean diet won: 87 events against 111.[1] One detail in the same paper governs how you should apply that.

## The trial

A single-center randomized trial at Reina Sofia University Hospital in Córdoba, Spain. Patients aged 20 to 75 with established coronary heart disease were assigned one-to-one to a Mediterranean diet or a low-fat diet, delivered by a team of dietitians. Physicians, investigators and the clinical endpoint committee were masked; participants obviously could not be, because people know what they are eating.[1]

*CORDIOPREV primary endpoint over 7 years, by intention to treat.[1]*

|   | Mediterranean (n = 502) | Low-fat (n = 500) |
| --- | --- | --- |
| Primary endpoint events | 87 | 111 |
| Crude rate per 1,000 person-years | **28.1** | 37.7 |
| Adjusted hazard ratios | 0.719–0.753 in favor of Mediterranean | — |

A log-rank p of 0.039 and adjusted hazard ratios whose confidence intervals stop just short of 1 (0.541–0.957 at one end, 0.568–0.998 at the other) describe a real but not overwhelming margin. The result stands, though it would not have survived much more attrition.

## The finding that is usually dropped

The effect was concentrated in men. Among 414 men on the Mediterranean diet, 67 (16.2%) had a primary endpoint event, against 94 of 413 (22.8%) on the low-fat diet, a multiadjusted hazard ratio of 0.669 (log-rank p = 0.013). Among the 175 women in the trial, **no difference was found between the groups**.[1]

> **82.5% of the participants were men.** With 175 women split across two arms, the trial was not powered to detect a difference in them, so “no difference found” is not the same as “no benefit exists”. Nor can the headline hazard ratio be quoted to a woman as though it had been demonstrated in her. Both are true at once.

## How to read it if you are on a GLP-1

This trial is *secondary* prevention: everyone in it had already been diagnosed with coronary heart disease. It does not establish what a Mediterranean diet does for someone without that diagnosis, and it was not a weight-loss trial. The endpoint was cardiovascular events, not kilograms.

What it does offer is unusual: a dietary pattern tested to the standard we expect of drugs. Most nutrition advice you will meet alongside a GLP-1 has nothing like this behind it. If you have established heart disease, this is the strongest dietary evidence in the field, and it is worth raising with your cardiologist.

- Secondary prevention in people with existing coronary heart disease. Not a general-population result.
- Seven years, hard clinical endpoints and diets delivered by dietitians. This is a randomized trial, not a study built on a self-reported food-frequency questionnaire.
- Benefit clear in men; no difference detected among the 175 women, who were too few to power the comparison.
- Not a weight-loss trial. Nothing here says a Mediterranean diet outperforms another for losing weight.
- Diet changes alongside a GLP-1 can affect glucose control and medication needs, so coordinate them with whoever prescribes.

For what the drugs themselves do on cardiovascular endpoints, see [where the evidence is strongest](https://glpwatchdog.org/research/where-the-evidence-is-strongest); for the protein side of eating well during weight loss, [protein targets and the lab panel](https://glpwatchdog.org/research/protein-targets-and-the-lab-panel).

## Frequently asked questions

### Is the Mediterranean diet better than a low-fat diet?

In people with established coronary heart disease, CORDIOPREV found it superior for preventing major cardiovascular events over seven years: 87 events against 111, a crude rate of 28.1 per 1,000 person-years against 37.7, with adjusted hazard ratios of 0.719 to 0.753.

### Did it work equally for men and women?

No. The benefit was clear in men, with a multiadjusted hazard ratio of 0.669. Among the 175 women in the trial no difference was found between the diets. With 82.5% of participants male, the trial was not powered to detect an effect in women, so that is an absence of evidence rather than evidence of absence.

### Does this apply if I do not have heart disease?

Not directly. CORDIOPREV was a secondary prevention trial: every participant had already been diagnosed with coronary heart disease. It does not establish what the diet does for someone without that diagnosis.

### Is it a weight-loss diet?

That was not what the trial measured. The endpoint was a composite of heart attack, revascularization, ischemic stroke, peripheral artery disease and cardiovascular death. Nothing here compares the two diets for weight loss.

## References

1. Delgado-Lista J, Alcala-Diaz JF, Torres-Peña JD, et al. Long-term secondary prevention of cardiovascular disease with a Mediterranean diet and a low-fat diet (CORDIOPREV): a randomised controlled trial. The Lancet. 2022. PMID: 35525255. https://pubmed.ncbi.nlm.nih.gov/35525255/

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Cite as: GLP Watchdog, Ruth Calder, "The Mediterranean Diet Trial That Measured Heart Attacks, Not Weight", published 2026-08-21, updated 2026-10-27. https://glpwatchdog.org/research/mediterranean-diet-the-outcome-trial

Canonical HTML page: https://glpwatchdog.org/research/mediterranean-diet-the-outcome-trial

Medical disclaimer: Nothing here is medical advice. We report on this subject; we do not treat anyone. Whether to begin a medication, supplement, or treatment, whether to adjust it, and whether to stop are questions for a clinician licensed to answer them, who knows your history.