The silent buildup of plaque in the arteries is a key risk factor for heart attacks and strokes. Clinical trials now reveal which dietary patterns may help reverse this dangerous process and strengthen cardiovascular health. This article walks through the evidence—randomized controlled trials examining direct plaque measurements, plus indirect data from cholesterol research—and synthesises a clear dietary pattern supported by the science.
The trials reviewed here represent our gold standard for investigating these questions. Some included other lifestyle factors alongside diet, and those confounders are addressed explicitly. The indirect cholesterol evidence then reinforces the conclusions. Together, they point to a consistent pattern of eating that can support healthy arteries and reduce the likelihood of serious cardiovascular events.
Table of Contents
Trial 1: Lifestyle Heart Trial
Section 3: The Best Diet Pattern
Section 1: The Diet Trials
This section covers five significant trials that examine how diet influences arterial plaque, presented in chronological order from oldest to most recent. All participants had some level of heart disease risk and were assigned to carefully designed study groups to produce high-quality results. Each trial contributes a vital piece to the puzzle of how dietary change affects cardiovascular health.
Trial 1: Lifestyle Heart Trial
The first study is the Lifestyle Heart Trial, published in 1990. The central question: can major lifestyle changes affect plaque buildup in the arteries after one year?
- Study Participants: All had coronary artery disease with significant plaque buildup.
- Intervention Group:
- Ate a low-fat vegetarian diet (fruits, vegetables, grains, legumes, egg whites, and non-fat dairy).
- Quit smoking.
- Added aerobic exercise.
- Received stress-management training and group support.
- Control Group:
- Was not asked to make any specific changes.
Researchers measured blood vessels in the heart using coronary angiography at the start and end of the trial. Results in the intervention group:
- 82% of participants saw a reversal in the narrowing of their arteries.
- Average blockage decreased from 40% of the artery's diameter to 37.8%.
- When blockages were more severe (>50%), the average regression was from 61.1% to 55.8%.
By contrast, blockages in the control group worsened, going from an average of 42.7% to 46.1% [1].
Those in the low-fat group also saw dramatic improvements in heart disease symptoms:
- 91% reduction in the frequency of chest pain (angina).
- 41% reduction in how long episodes lasted.
- 28% decrease in severity.
Meanwhile, the control group's angina became more frequent (+165%), longer in duration (+95%), and more severe (+39%) [1].
Researchers followed up with the same participants at the five-year mark. In the intervention group, average plaque blockage continued to shrink from 37.8% (at one year) to 37.3% (at five years). In the control group, blockages worsened from 42.3% (at one year) to 51.9% (at five years) [2].
From this first study, a low-fat, whole-food diet combined with other lifestyle changes produced a significant effect on plaque buildup. However, because so many lifestyle factors changed at once—quitting smoking, stress reduction, and exercise—it is not possible to isolate precisely how much of the benefit came from diet alone.
Trial 2: STARS Trial
Next is the STARS trial, published in 1992. Like the Lifestyle Heart Trial, participants already had heart disease. This time, there were three groups:
1. Usual care (Control Group)
2. Diet-Only Intervention Group: Adopted a low-fat diet high in fiber.
3. Diet + Medication Group: Adopted the same low-fat, high-fiber diet and took a cholesterol-lowering medication.
After 39 months, close to half of the control group experienced further plaque narrowing. By contrast, the arteries of participants in both intervention groups widened, although the increase was modest and reached statistical significance mainly in the diet + medication group. Even so, cardiovascular events dropped dramatically in both intervention groups compared to the control. The overall number of events was small, but the results suggest that diet alone can move the needle on artery health.
This trial indicates that a low-fat diet plus added fiber can support cardiac health without other lifestyle changes. The previous trial that included additional lifestyle interventions saw greater impact, leaving open the possibility that combining dietary change with other healthy habits is even more effective—or that a different diet altogether might produce stronger results.
Trial 3: PREDIMED Study
The PREDIMED study, published in 2013, recruited individuals at high risk for heart disease and divided them into three groups:
- Control: A low-fat diet.
- Intervention Group 1: A Mediterranean diet supplemented with extra virgin olive oil (EVOO).
- Intervention Group 2: The same Mediterranean diet but supplemented with mixed nuts.
Instead of coronary angiography, researchers used ultrasound to measure the thickness of the artery walls in the neck—known as carotid intima-media thickness (IMT). This thickness is a well-established surrogate measure for atherosclerotic plaque buildup.
After an average of 2.4 years:
- The low-fat control group saw increases in arterial wall thickness.
- The Mediterranean group with nuts had a decrease in average wall thickness.
- The Mediterranean group with olive oil showed no significant change in thickness [3].
By demonstrating that a diet with higher unsaturated fat could outperform a low-fat diet in this context, PREDIMED delivered an important insight. However, more data were needed to confirm whether extra virgin olive oil and other unsaturated fats bring unique long-term benefits.
Trial 4: CORDIOPREV Trial
The CORDIOPREV trial provides another look at the Mediterranean diet's impact. Nearly 1,000 people with heart disease took part in this study. As in PREDIMED, researchers used ultrasound to track changes in carotid artery thickness at baseline, at five years, and again at seven years.
- Mediterranean Diet Group: Carotid artery thickness decreased sharply by the five-year mark, and even more by year seven.
- Low-Fat Group: No change was detected over the same timeframe [4].
These results further underscore the potential of a Mediterranean-style diet—one higher in unsaturated fats—to reduce arterial plaque markers and improve cardiovascular outcomes.
Trial 5: DISCO Trial
The final trial examines the DASH diet (Dietary Approaches to Stop Hypertension). The DASH diet is rich in:
- Fruits
- Vegetables
- Whole grains
- Low-fat dairy
It typically avoids saturated fats, cholesterol, starchy foods, and sweets. This trial had two groups:
1. DASH Diet + Medication
2. Medication-Only
Researchers used advanced imaging to measure total plaque volume in a specific segment of the coronary arteries at the start and after approximately one year.
- In the medication-only group, overall plaque volume increased slightly.
- In the DASH + medication group, there was no significant overall change in plaque volume—an improvement compared to the medication-only group.
- For non-calcified plaque, which is softer and more vulnerable to rupture, both groups saw reductions, but the reduction was greater in the group following the DASH diet plus medication [5].
Taken together, these five trials show that diets low in saturated fat, high in fiber, and often higher in unsaturated fats—combined with an overall healthy lifestyle—can help reverse or slow plaque buildup in the arteries. The early trials emphasized low-fat vegetarian patterns, whereas the more recent ones highlighted Mediterranean and DASH diets. They all reinforce that dietary choices substantially affect plaque, although the specific details (for example, how much and which type of fat) may vary.
Section 2: Indirect Evidence
At this point, there is direct evidence from five major trials indicating that specific diets can reduce or stabilise plaque buildup. Cholesterol levels—particularly LDL cholesterol—also play a central role in whether plaque forms or regresses.
A meta-analysis of 31 studies found that treatments lowering LDL cholesterol significantly reduced plaque volume [6]. Another influential study, the PESA (Progression of Early Subclinical Atherosclerosis) study, noted that once LDL cholesterol surpasses about 50–60 mg/dL, plaque can begin to develop, and risk rises as LDL levels go higher [7].
In fact, some researchers speculate that an LDL level as low as 20–40 mg/dL might be optimal [8].
Because higher LDL is tied to more plaque, and lowering LDL can reduce plaque, it follows that a diet shown to lower LDL cholesterol should help with plaque reduction. Saturated fats tend to raise LDL cholesterol [9]. Conversely, diets high in fiber and abundant in fruits, vegetables, and whole grains generally lower LDL.
One study demonstrated that a specific diet produced a 9.2% reduction in LDL cholesterol in just eight weeks [10]. Participants were split into three eating patterns:
- Control: A typical American diet.
- More Fruit, Vegetables, and Whole Grains: Also reduced sweets somewhat.
- DASH Diet: Rich in fruits, vegetables, whole grains, and low-fat dairy, while minimising red meat, sweets, and saturated fats.
The third group following the full DASH eating plan saw the most robust drop in LDL.
All this aligns with the direct plaque trial data. Diets that limit saturated fats, include healthy (unsaturated) fats, and feature plenty of fiber-rich foods can lower LDL cholesterol and, by extension, slow or reverse the accumulation of plaque.
Section 3: The Best Diet Pattern
Having walked through the direct and indirect evidence, the research points to a clear dietary framework for heart health and plaque reduction.
The Role of Fat
The first two trials showed that a low-fat diet can help with arterial plaque. However, more recent trials—including PREDIMED and CORDIOPREV—show that a diet higher in unsaturated fats, particularly the Mediterranean style, can be just as effective, if not more so. The key difference lies in avoiding saturated (and trans) fats while embracing healthy unsaturated fats found in foods like:
- Extra virgin olive oil
- Avocados
- Nuts and seeds
- Fatty fish (if animal proteins are included)
The Importance of Fiber
In the trials examined, participants consistently increased their intake of fruits, vegetables, legumes, and whole grains. These foods are loaded with fiber, which helps reduce LDL cholesterol [11]. Fiber works through several mechanisms: soluble fiber (found in oats, legumes, and psyllium husk) binds bile acids in the gut, prompting the liver to draw more cholesterol from the bloodstream to make new bile acids; insoluble fiber supports a diverse gut microbiome, which in turn modulates inflammatory pathways relevant to plaque development. Prioritising fiber is a central reason why diets such as the Mediterranean, DASH, and certain low-fat vegetarian approaches are all associated with improved heart health outcomes.
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Avoiding Sugar
Modern diets often include significant amounts of added sugars—from sweetened beverages to desserts and refined cereals. High sugar consumption is linked to increased cardiovascular disease risk [12].
The dietary patterns most successful in reducing plaque (Mediterranean, DASH, low-fat whole-food) are all relatively low in added sugars.
Getting Enough Protein
Both the Mediterranean and DASH diets provide 15–18% of total calories from protein, which is more than the typical 10% found in many older dietary patterns. Adequate protein intake is essential for maintaining muscle mass, especially with age, and research suggests it may help reduce cardiovascular risk. But protein source matters.
Large-scale observational data spanning 30 years showed that individuals eating a higher ratio of plant-based proteins experienced a 27% lower risk of blockages in the coronary arteries. Even more compelling, those who ate the most plant protein and had a higher overall protein intake had a 46% lower risk of heart disease compared to those who ate the least plant protein and had the lowest total protein intake [13].
Plant-based proteins come packaged with fiber and other beneficial nutrients, while many animal proteins carry a higher saturated fat load. That said, this does not mean eliminating animal protein. Instead, the evidence suggests limiting processed and fatty red meats in favour of leaner cuts, fish, or poultry—while increasing overall plant protein sources such as beans, legumes, nuts, and seeds.
Getting Enough Potassium
The Mediterranean and DASH diets both feature foods rich in potassium—including beans, leafy greens, peas, beets, many other vegetables, and low-fat dairy. Adequate potassium helps lower blood pressure, another key factor for cardiovascular health. Potassium counteracts the blood-pressure-raising effect of sodium by promoting sodium excretion through the kidneys and relaxing blood vessel walls. Most adults in Western countries consume far less potassium than recommended, which is one reason whole-food dietary patterns show consistent blood-pressure benefits over typical diets dominated by processed foods.
Putting It All Together
Here is a concise breakdown of what the research supports as the optimal eating strategy to help prevent or slow artery clogging:
- Limit Saturated Fats: Found mainly in butter, high-fat dairy, and fatty cuts of meat.
- Embrace Unsaturated Fats: Focus on extra virgin olive oil, avocados, nuts, and seeds.
- Pack in Fiber: From fruits, vegetables, legumes, and whole grains.
- Cut Back on Added Sugars: Reduce sugary drinks and desserts.
- Aim for Adequate Protein: Around 15–18% of total calories, leaning toward plant-based sources.
Both the Mediterranean and DASH diets meet these criteria well, but they are not the only options. These principles can be adapted to different culinary traditions. The main takeaway is to avoid saturated fats, choose healthy unsaturated fats, maximise fiber intake, and cut out added sugars. Consistently applying these principles stacks the odds in favour of preventing the harmful buildup of plaque in the arteries.
Reference List
1. https://www.sciencedirect.com/science/article/abs/pii/014067369091656U
2. https://www.acc.org/latest-in-cardiology/clinical-trials/2010/02/23/19/10/lht---long-term-follow-up
3. https://www.ahajournals.org/doi/10.1161/ATVBAHA.113.302327
4. https://www.ahajournals.org/doi/10.1161/STROKEAHA.120.033214
5. https://www.sciencedirect.com/science/article/pii/S1936878X20309414?via%3Dihub
6. https://www.nature.com/articles/s41598-021-87528-w
7. https://www.sciencedirect.com/science/article/pii/S0735109721051159
8. https://www.sciencedirect.com/science/article/pii/S2666667722000551
9. https://pmc.ncbi.nlm.nih.gov/articles/PMC2943062/
10. https://www.sciencedirect.com/science/article/pii/S0002916523062706
11. https://www.mdpi.com/2072-6643/11/5/1155
12. https://pubmed.ncbi.nlm.nih.gov/24493081/
13. https://ajcn.nutrition.org/article/S0002-9165(24)00737-8/fulltext
