The Planetary Health Diet and Your Heart: What a 13,000-Person Study Found

Reviewed by the HealthyMag Editorial Team. Last updated: June 2026.

A diet originally designed to feed 10 billion people without wrecking the planet may also be good for your heart. That is the headline from a major analysis published in the Journal of the American Heart Association, which tracked thousands of U.S. adults for nearly three decades and found that the closer people stuck to the EAT-Lancet “Planetary Health Diet,” the lower their risk of heart disease, stroke, and heart failure.

The finding adds U.S. long-term data to a fast-growing pile of research — from the UK, Spain, and earlier American cohorts — all pointing in the same direction: an eating pattern built for environmental sustainability happens to overlap almost perfectly with the eating pattern cardiologists have recommended for decades. Here is what the study actually found, what the diet looks like on a plate, and what it can and cannot prove.

What the study found

The research, titled “Healthy Eating for the Planet, Cardiovascular Health, and Longevity,” was led by Jiaqi Yang, Valerie K. Sullivan, and Casey M. Rebholz of Johns Hopkins, and published in the Journal of the American Heart Association in July 2025. It drew on the long-running ARIC study (Atherosclerosis Risk in Communities), which has followed middle-aged Americans since the late 1980s.

The team scored the diets of 13,444 adults who were free of cardiovascular disease at the start, using the Planetary Health Diet Index (PHDI) — a 0-to-135 scale that rewards plant-forward eating. Over a median follow-up of 29 years, the researchers documented 5,074 cardiovascular events, 2,512 deaths from cardiovascular causes, and 8,436 deaths from any cause. That is an unusually long and complete follow-up window, which makes the results harder to dismiss.

For every 20-point increase in PHDI score — roughly the gap between a typical Western diet and a genuinely plant-forward one — participants had:

• 13% lower risk of coronary heart disease
• 16% lower risk of stroke
• 9% lower risk of heart failure
• 13% lower risk of dying from cardiovascular disease
• 10% lower risk of dying from any cause

The average participant scored about 76 on the index, well short of the ceiling — which means most people had room to improve, and the data suggest that moving up the scale paid off across every outcome the team measured.

What the EAT-Lancet “Planetary Health Diet” actually is

The Planetary Health Diet was introduced in 2019 by the EAT-Lancet Commission, a group of scientists who set out to answer a single question: what would humanity have to eat to keep both people and the planet healthy through 2050? Their answer was not a fad or a brand. It was a flexible, mostly plant-based template that leaves room for small amounts of animal foods.

The Planetary Health Diet Index used in the study scores 14 food groups. Some raise your score; others lower it. The pattern is strikingly close to the Mediterranean diet and to standard heart-healthy advice — lots of plants, healthy fats, and far less red and processed meat and added sugar.

The point is not to go fully vegan. The Planetary Health Diet allows modest servings of fish, poultry, dairy, and even occasional red meat. What earns the high scores — and, in this study, the lower disease risk — is the overall balance tilting heavily toward whole plant foods.

Why it may protect the heart

Researchers have a fairly clear set of mechanisms for why a plant-forward pattern would help the cardiovascular system, and they line up with decades of nutrition science.

Diets rich in vegetables, fruit, whole grains, legumes, and nuts deliver large amounts of fiber, potassium, polyphenols, and unsaturated fats while cutting back on the saturated fat and sodium that drive up LDL cholesterol and blood pressure. Fiber and unsaturated fats help lower LDL; potassium helps relax blood vessels; and the colorful plant compounds (polyphenols) appear to dampen the chronic, low-grade inflammation that quietly damages arteries over time. Some of these foods are studied individually for exactly these effects — for example, the nitrates in vegetables like beets, which we covered in our look at beetroot juice for blood pressure and endurance.

Cutting red and processed meat matters too. Processed meats are consistently linked to higher cardiovascular risk, and replacing them with legumes or fish shifts the fat profile toward heart-protective unsaturated fats. The same anti-inflammatory logic that may protect the heart is being explored for the brain as well; a separate 2026 analysis we covered found a similar plant-forward, anti-inflammatory pattern was associated with lower dementia risk in our report on the anti-inflammatory diet and dementia.

There is also a subtraction effect worth noting. Diets heavy in ultra-processed foods tend to be high in sodium and additives, which can push blood pressure up — a pattern highlighted in our coverage of common food preservatives linked to high blood pressure. A Planetary Health Diet, by design, crowds those foods out.

What the research can — and can’t — prove

This is the part that gets lost in headlines. The ARIC analysis is an observational cohort study, not a randomized trial. It can show a strong, consistent association between eating this way and having a healthier heart. It cannot prove that the diet directly causes the lower risk.

The reason is confounding. People who score high on the Planetary Health Diet Index also tend to exercise more, smoke less, drink less, have more education, and see doctors more regularly. Good studies like this one statistically adjust for those factors — but, as the authors themselves note, “residual and unmeasured confounding cannot be completely ruled out.” Some of the benefit credited to the diet could belong to the healthier lifestyle that often travels with it.

There are other caveats specific to this dataset. Diet was measured by self-reported questionnaires, which are imperfect. The dietary data were collected in the late 1980s and mid-1990s, so they may not reflect how people eat today. And the ARIC food survey did not capture soy foods, which the authors say may have caused them to underestimate the diet’s benefits.

What makes the finding credible despite these limits is consistency. This is not a lone result. A 2024 study in The Lancet Planetary Health followed nearly 194,000 U.S. women and men and found those most closely following the diet had a 17% lower risk of total cardiovascular disease. A 2025 analysis of more than 118,000 people in the UK Biobank found a 14% lower risk. When multiple large cohorts across different countries point the same direction, the signal is harder to write off as a fluke.

Practical takeaways: how to eat this way

You do not need to overhaul your diet overnight or memorize an index score. The Planetary Health Diet is more of a direction than a rulebook, and the ARIC data suggest that even moving partway up the scale matters. A few concrete shifts:

• Make plants the base of the plate. Aim for vegetables, whole grains, and legumes to fill most of your plate, with animal foods as a side rather than the centerpiece.
• Swap red and processed meat for legumes or fish. Beans, lentils, and fish a few times a week deliver protein with a far better fat profile. Processed meats — bacon, deli meats, hot dogs — are the ones to minimize.
• Choose whole grains over refined. Brown rice, oats, whole-wheat bread, and barley over white bread and white rice.
• Use unsaturated fats. Olive oil, nuts, seeds, and avocado in place of butter and processed snacks.
• Cut back on added sugar and ultra-processed foods. These pull your score — and likely your cardiovascular risk — in the wrong direction.
• Keep dairy, poultry, and eggs modest, not absent. The diet allows them; it just doesn’t build around them.

If you have existing heart disease, kidney disease, diabetes, or you take medications affected by diet (such as blood thinners or potassium-sensitive drugs), talk with your doctor or a registered dietitian before making big changes.

Frequently Asked Questions

What is the Planetary Health Diet?

It is a flexible, mostly plant-based eating pattern introduced by the EAT-Lancet Commission in 2019, designed to be both healthy for people and sustainable for the planet. It emphasizes vegetables, fruit, whole grains, legumes, nuts, and healthy fats, with small amounts of fish, poultry, dairy, and red meat.

Is the Planetary Health Diet the same as a vegan diet?

No. It is plant-forward but not strictly plant-only. The diet allows modest servings of fish, poultry, eggs, dairy, and even occasional red meat. The goal is to shift the balance heavily toward plants, not to eliminate animal foods entirely.

How much did the diet lower heart disease risk in the 2025 study?

In the ARIC study, every 20-point increase in the Planetary Health Diet Index was associated with a 13% lower risk of coronary heart disease, a 16% lower risk of stroke, and a 9% lower risk of heart failure, along with a 13% lower risk of cardiovascular death.

Does this study prove the diet prevents heart disease?

No. It is an observational study, which can show a strong association but cannot prove cause and effect. People who follow the diet also tend to have other healthy habits, and some of the benefit may come from those. Still, the consistency of findings across multiple large studies strengthens the case.

How is the Planetary Health Diet different from the Mediterranean diet?

They overlap heavily — both emphasize vegetables, whole grains, legumes, nuts, fish, and olive oil while limiting red meat and added sugar. The Planetary Health Diet was designed with environmental sustainability in mind, so it places extra emphasis on reducing red and processed meat, but on the plate the two patterns look very similar.

What foods raise your Planetary Health Diet Index score?

Whole grains, vegetables, whole fruit, legumes, nuts, fish and shellfish, unsaturated plant fats, and moderate amounts of poultry and dairy raise your score. Red and processed meat, added sugar, saturated fat, large amounts of eggs, and starchy tubers lower it.

Do I have to follow the diet perfectly to benefit?

The data suggest not. The average score in the study was about 76 out of 135, and risk dropped progressively as scores rose. That implies even partial improvements — eating more plants and less processed meat — are associated with measurable benefit, without needing a perfect score.

Is the Planetary Health Diet good for the environment too?

That was its original purpose. The EAT-Lancet Commission designed it to reduce the environmental footprint of food — particularly the greenhouse gases, land, and water tied to red meat production — while still meeting human nutritional needs. The cardiovascular benefits are, in a sense, a bonus that happens to align with sustainability.

The Bottom Line

A nearly three-decade study of more than 13,000 Americans adds strong evidence that the EAT-Lancet Planetary Health Diet — a plant-forward pattern with modest animal foods — is associated with meaningfully lower risk of coronary heart disease, stroke, heart failure, and cardiovascular death. The effect sizes (9% to 16% lower risk per 20-point dietary improvement) are consistent with what UK and other U.S. cohorts have found, which lends the finding weight.

The important caveat is that this is observational research: it shows that people who eat this way tend to have healthier hearts, not that the diet single-handedly causes the difference. But the direction is unambiguous and the mechanisms are well understood. If you want one practical message, it is the same one nutrition science has been converging on for years — eat more plants, less red and processed meat, and less added sugar. The fact that doing so also lightens your environmental footprint is a rare case where what is good for you and what is good for the planet point the same way.

Sources

1. Yang J, Sullivan VK, Rebholz CM. “Healthy Eating for the Planet, Cardiovascular Health, and Longevity: An Observational Study,” Journal of the American Heart Association, 2025. https://www.ahajournals.org/doi/10.1161/JAHA.124.040610
2. Sawicki CM, et al. “Planetary health diet and cardiovascular disease: results from three large prospective cohort studies in the USA,” The Lancet Planetary Health, 2024. https://pubmed.ncbi.nlm.nih.gov/39243782/
3. Sotos-Prieto M, et al. “Association between planetary health diet and cardiovascular disease: a prospective study from the UK Biobank,” European Journal of Preventive Cardiology, 2025. https://academic.oup.com/eurjpc/article/32/5/394/7745359