Changing diet guidelines frustrate consumers
DEAR DOCTOR: It seems like if you just wait long enough, everything about nutrition gets contradicted. So now fat is good, carbs are bad, and we don’t really need more than 4 servings of vegetables a day?
DEAR READER:
When it comes to why nutrition advice keeps changing, several factors come into play: science, media and marketing.
When researchers publish results that suggest a causal link between a certain food and a particular outcome, they acknowledge that it’s just one single data point in an ongoing analysis. It takes time and repetition to reach a reliable conclusion. But scientific rigor pretty much flies out the window when it comes to how the emerging studies get publicized, which leads us to the second factor: the media.
While scientists are saying, “In this one study, we see a link between eggs and heart disease,” in the hands of overeager newscasters, this is translated as “Eggs will kill you!” Meanwhile, time goes on. Many more studies are conducted. A decade or so later, armed with a wealth of data points collected over the
years, the original thesis doesn’t hold up. For the scientists, it’s the nature of research — precision and repetition over time. For the rest of us, it’s a new — and contradictory — headline. “Eggs are good!”
Which brings us to marketing. Diet and nutrition are multibillion-dollar industries in the United States. That means that as food recommendations are crafted, a good bit of lobbying takes place. When new dietary guidelines were released in 2015, a number of nutrition experts bemoaned the influence of the food industry in the process.
We need to be savvy consumers of dietary information. And when it comes down to healthful eating, stick with the tried-and-true basics. That is, eat fish and lean meats, grains and legumes. Limit or cut out processed foods, and eat a wide variety of fruits and vegetables, especially leafy greens. Limit sugar and alcohol. When you’re thirsty, reach for a glass of water.
Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health.