Based on years of low-fat messaging, most Americans still actively avoid dietary fat, while eating far too much refined carbohydrates. This fear of fat also drives industry formulations, with heavy marketing of fat-reduced products of dubious health value.

Recent research has established the futility of focusing on low-fat foods. Confirming many other observations, large randomized trials in 2006 and 2013 showed that a low-fat diet had no significant benefits for heart disease, stroke, diabetes or cancer risks, while a high-fat, Mediterranean-style diet rich in nuts or extra-virgin olive oil — exceeding 40 percent of calories in total fat — significantly reduced cardiovascular disease, diabetes and long-term weight gain. Other studies have shown that high-fat diets are similar to, or better than, low-fat diets for short-term weight loss, and that types of foods, rather than fat content, relate to long-term weight gain.

This is not to say that high-fat diets are always healthy, or low-fat diets always harmful. But rather than focusing on total fat or other numbers on the back of the package, the emphasis should be on eating more minimally processed fruits, nuts, vegetables, beans, fish, yogurt, vegetable oils and whole grains in place of refined grains, white potatoes, added sugars and processed meats. How much we eat is also determined by what we eat: Cutting calories without improving food quality rarely produces long-term weight loss.