This is about people who already have heart disease, not just those trying to avoid it. A systematic review and meta-analysis pooled 40 reports — 6 randomized trials, 30 observational studies, and 4 nonrandomized comparisons — covering at least 260,354 patients previously diagnosed with coronary heart disease (CHD). The question: does sticking with a Mediterranean-style diet and staying physically active actually change what happens next, after a CHD diagnosis.
The strongest single piece of evidence came from an actual randomized trial. Comparing a Mediterranean diet against a low-fat diet, the Mediterranean diet was linked to a lower risk of major adverse cardiovascular events — MACE, meaning things like heart attack, stroke, or cardiovascular death (HR 0.72, 95% CI 0.54 to 0.96, rated moderate certainty). The observational evidence pointed the same direction: closer adherence to a Mediterranean diet was linked to lower all-cause mortality (HR 0.74, 95% CI 0.60 to 0.90, I² = 44%), though the link to cardiovascular-specific mortality was less certain.
Staying physically active showed an even larger association. Compared with people who stayed inactive, those who maintained or resumed physical activity after their CHD diagnosis had lower all-cause mortality (HR 0.64, 95% CI 0.55 to 0.74, I² = 29%) and notably lower cardiovascular mortality (HR 0.42, 95% CI 0.28 to 0.64, I² = 72%) — less than half the risk in the pooled estimate.
The evidence quality isn't uniform, and the review is upfront about that. Only 6 of the 40 included reports were randomized trials; the rest were observational, which means diet and activity levels weren't assigned but self-selected — people who stay active after a heart diagnosis may differ in other health-relevant ways too. Randomized evidence specifically testing exercise programs, or combined diet-and-activity programs, was described as sparse. The one randomized diet comparison (Mediterranean vs. low-fat) is the most trustworthy single data point here; the rest builds a consistent but less certain picture around it.
Who this applies to. This is specifically about secondary prevention — people managing an existing CHD diagnosis, not general population diet advice. No conflicts of interest were declared.
Bottom line. In people with existing coronary heart disease, closer adherence to a Mediterranean diet and staying physically active were both linked to meaningfully lower mortality risk — with the diet finding backed by an actual randomized comparison (27% lower MACE risk) and the activity finding, while larger, resting more on observational data. Neither replaces standard cardiac care, but both look like reasonable, low-risk additions to discuss with a cardiologist.
Medical note. This article is for general educational purposes and should not be considered personal medical advice.