A. Judith C. Thalheimer, RD, LDN, managing editor of Tufts Health & Nutrition Letter, answers: “There are several factors that lead to confusion around nutrition advice. One is that nutrition science, like any other scientific disciplines, is always evolving. A more significant cause of confusion is the way this evolving research is conveyed to the public. The media often reports on a single study as if it represents new advice, when what it really represents is one more small piece of a very large and complex puzzle. Let’s say yesterday you saw a news report that drinking coffee is good for health, but today the press is reporting on a study that says it’s bad. The studies could have looked at the effects of different amounts of coffee intake, different populations, and/or different health outcomes, or one (or both) studies could be flawed. It’s also possible that coffee drinking (for example) could have some positive and some negative impacts on health. Remember that one study with a surprising or controversial result will get lots of media attention, even if 99 other well-conducted studies reached the opposite conclusion. Rather than change your behavior based on the latest headline, wait for official guidelines, such as recommendations from government agencies (including the Dietary Guidelines for Americans) and independent organizations like the American Heart Association, American Diabetes Association, and American Cancer Society. These expert committees review ALL of the research on a topic, so you don’t have to. They draw conclusions based on the TOTALITY of the evidence.
“The most concerning reason for confusion around dietary advice is marketing. People who want to sell you something (be it a food, a supplement, or a diet book or program) have a financial motivation to cherry pick research, or even bend the facts to fit their theories. It can be very difficult to separate good advice from suspect information. A truly trustworthy source would include an open discussion of research that disagrees with their point, not just studies that back up their claims.
“It may feel like nutrition advice is always changing, but true nutrition experts will tell you that basic dietary advice has not changed in many decades.”