Regardless of who issues them, guidelines for health promotion and disease prevention universally recommend diets that are largely plant-based, meaning those that include plenty of fruits, vegetables, grains, beans, and nuts. The U.S. dietary guidelines also recommend foods in the “protein” category. Grains, beans, and nuts are good sources of protein, but the guidelines use “protein” to mean low-fat dairy, lean meats, and fish. Recommended eating patterns include all these foods, relatively unprocessed, but with minimal addition of salt and sugars. Such patterns provide nutrients and energy in proportions that meet physiological needs but also minimize the risk of obesity, type 2 diabetes, and other chronic diseases. One more definition: “Patterns” refer to diets as a whole, not to single foods. No one food makes a diet healthful. The healthiest diets include a wide variety of foods in each of the recommended categories in amounts that balance calories.

In their largely unprocessed forms, foods from the earth, trees, or animals are healthful by definition. So why, you might ask, would the producers of foods such as cranberries, pears, avocados, or walnuts fund research aimed at proving that these particular foods—rather than fruits, vegetables, or nuts in general—have special health benefits? Marketing, of course. Every food producer wants to expand sales. Health claims sell.

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