Heart-healthy eating: How does your diet stack up?

When you consider that 80% of heart disease can be prevented by healthy lifestyle habits, it makes sense to prioritize the one habit you can't live without: eating. But many people — including doctors — aren't sure which diets are best for keeping your heart healthy.

This problem was the inspiration behind a recent scientific statement from the American Heart Association (AHA), published May 30, 2023, in Circulation, says Dr. Frank Hu, professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health. "People hear about all sorts of popular diets in the news and on social media. But they don't have a good sense about which ones actually have scientific evidence behind them," he says. Neither do most doctors, as they receive very little nutrition training as part of their education. (Note that although the word "diet" is often associated with weight loss, it more generally refers to the kinds of foods people typically eat.)

Evidence-based ranking

The statement ranks 10 popular diets based on how well they align with the AHA's dietary guidelines, which recommend limiting saturated fat and excess carbohydrates, especially highly processed carbs and sugary drinks (see "Popular diets: Common names, key features, and rankings"). The evidence comes from decades of randomized trials, population-based studies, and other research, says Dr. Hu, who served as a reviewer for the scientific statement.

"It's no surprise that all of the top-tier diets are mostly plant-based," says Kathy McManus, director of the Department of Nutrition at Harvard-affiliated Brigham and Women's Hospital. Vegetables, fruits, whole grains, beans, and nuts are all naturally low in saturated fat. They're also good sources of fiber and contain a variety of antioxidants. "What I like about the DASH and Mediterranean diets is that they include fish, which is a good source of both healthy fats and protein," she says. Canned fish, such as sardines, herring, and tuna, are affordable options, she adds. But these two diets (along with various iterations of vegetarian-style eating patterns) can also include a range of other healthy proteins, like beans, nuts, poultry, dairy products, and eggs.

Another reason the top two diets get high marks is that they encourage people to limit refined grains and added sugars. "A healthy dietary pattern should focus on whole, real foods and limit processed foods, which tend to add extra salt, sugar, and fat into your diet," says McManus. Over all, vegetarian and pescatarian diets tend to be quite healthy, but not if people simply avoid meat and fill up on processed foods, she adds.

Be flexible

Don't feel you have to abandon the familiar foods you grew up eating. "Following cultural traditions and preferences is important for helping people stay with a diet over the long term," says Dr. Hu.

McManus agrees. "You might need to make some adjustments to how your traditional favorite foods are prepared by swapping in a healthier fat or using less sodium," she says. You'll be more likely to stick with healthy, lasting changes if you make small, gradual changes that are flexible, family-friendly, and realistic, she adds.

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