Is the portfolio diet the best diet ever?

News flash: What we eat can play a pivotal role in warding off — or treating — disease and enhancing quality of life. You may already believe this, and certainly mounting evidence supports that idea. But on the cluttered shelf of diets claiming top health benefits, which one ranks as the absolute best?

That’s a trick question. In fact, there is no single best diet. A good diet for me may be different from what’s best for you. And for either of us, there may be several good choices with no clear winner.

How can you choose the right diet for you?

When thinking about what diet might be best for you, ask yourself:

• What goals are most important? A goal might be weight loss, improved health, avoiding disease, or something else.
• How do you define “best”? For some people, best means the diet with the highest number of health benefits. For others, it may focus on one specific health benefit, such as lowering cholesterol. Still other people may prefer a diet that delivers the greatest benefit for the lowest cost. Or a diet that is healthy and also easy to stick with.
• What health problems do you have? One diet may have an advantage over another depending on whether you have cancer, cardiovascular disease, diabetes, or none of these.
• Which foods do you like best? Your tastes, culture, and location may shape your dietary preferences, and powerfully affect how likely you are to stick with a specific diet.

Which diets are high in health benefits?

Two very well studied diets demonstrate clear benefit, including lowering risk for heart disease and stroke and reducing high blood pressure: the Mediterranean diet and the DASH diet.

But the portfolio diet may be as good as or better than these plans, at least for combatting cardiovascular disease that contributes to clogged blood vessels, heart attacks, and stroke. What? You’ve never heard of the portfolio diet? You’re not alone.

What is the portfolio diet?

Just as a financial advisor may recommend having a diverse investment portfolio — not just stocks, not just bonds — the portfolio diet follows suit. This largely plant-based diet focuses on diverse foods and food groups proven to lower harmful blood lipids, including LDL (so-called bad cholesterol) and triglycerides.

If you choose to follow this eating pattern, you simply need to learn which foods have a healthy effect on blood lipids and choose them in place of other foods. For some people, this only requires small tweaks to embrace certain foods while downplaying other choices. Or it may call for a bigger upheaval of longtime eating patterns.

Which foods are encouraged in the portfolio diet?

Below are the basics. Eating more of these foods regularly may help lower levels of harmful blood lipids:

• plant-based proteins such as soy, beans, tofu, peas, nuts, and seeds
• high-fiber foods such as oats, barley, berries, apples, and citrus fruit; other examples include bran, berries, okra, and eggplant
• phytosterols, which are a natural compound in plant-based foods such as whole grains, fruits, vegetables, and nuts (other sources are foods fortified with phytosterols or dietary supplements)
• plant-based oils high in monounsaturated fat such as olive oil, avocado oil, safflower oil, and peanut oil.

See? Some of your favorite foods make the cut. That’s a major strength of this approach: the list of recommended foods is long. So, it’s likely that you’re already eating and enjoying some of the recommended foods.

Which foods are not part of the portfolio diet?

It’s worth highlighting foods that are not on this list, such as

• red meat
• highly processed foods
• refined grains and added sugar, which may contribute to chronic inflammation
• butter, cream, and other dairy products high in saturated fat and cholesterol.

What can the portfolio diet do for you?

Researchers have shown that the portfolio diet can improve blood lipids. But can it also lower the risk of heart attack, stroke, and other cardiovascular problems?

Yes, according to a 2023 study published in Circulation. More than nearly 17,000 people kept careful food diaries for 30 years. Those who most closely followed the portfolio diet, compared with those who followed it the least, were more likely to have favorable lipids and inflammation. They were also 14% less likely to have a heart attack, and 14% less likely to have a stroke.

This was true even after accounting for factors that could affect cardiovascular disease risk, such as taking cholesterol-lowering medications, exercise, smoking, or having diabetes or a family history of cardiovascular disease.

Because this was an observational study, it can’t conclusively prove that the portfolio diet, rather than another factor, was responsible for the observed cardiovascular benefits. And we don’t know how much benefit came from reducing or eliminating certain types of foods, rather than from the specific foods eaten.

Does the portfolio diet help people lose weight or deliver other health advantages?

What about the portfolio diet for weight loss? Although some people lose weight on the portfolio diet, it’s not billed as a weight-loss diet. Understanding its potential benefit for other conditions such as obesity, cognitive decline, diabetes, and cancer awaits further research.

Go beyond diet to boost health

Of course, diet is not the only way to improve cardiovascular health and your overall health. You’ll stay healthier by

• not smoking
• getting regular exercise
• maintaining a healthy blood pressure and weight
• preventing diabetes when possible, or getting good medical care to treat it if necessary
• taking prescribed medications such as cholesterol-lowering drugs.

The bottom line

It’s probably best to move past the idea of there being a single best diet. The overall pattern of your diet and your portion sizes are probably more important. For most people, it’s also a good idea to move away from restrictive diets that are nearly impossible to stick with and toward healthier overall eating patterns. The portfolio diet checks both those boxes.

There’s a lot of overlap between the portfolio diet and other healthy diets. So, no one should be suggesting it’s the best diet ever. But if you’re trying to eat healthier, it’s a great place to start.

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. … See Full Bio View all posts by Robert H. Shmerling, MD