Getting the whole story: an end to nutrient-based diet guides?

When you shop, are you looking for food or nutrients?
Do you shop for food or nutrients?

When moms talk about the trials and tribulations of feeding their children, the conversations typically center on what types of foods their kids like and dislike. How to get young Jim to eat green beans. Whether it’s healthy for Gracie to avoid meat entirely. You rarely hear parents discussing whether their kids are getting the right percentages of specific nutrients and additives, the correct amount of starch or sodium.

But while a nutrient-centric view of food isn’t in tune with how most people think about their food intake, it’s exactly how the U.S. government’s Dietary Guidelines for Americans approaches the subject. The guidelines, which are the basis for federal nutrition policy, focus not on the types of food people should be eating, but on specific nutrients found in foods. According to obesity expert David Ludwig, MD, PhD, director of Children’s Hospital Boston’s Optimal Weight for Life Program, these guidelines are difficult to translate into day-to-day life. He, along with colleague Dariush Mozaffarian, MD, DrPH, from the Harvard School of Public Health, recently published a commentary in the Journal of the American Medical Association that suggests creating food guidelines based on a whole food model, instead of nutrient-based quotas.

David Ludwig, MD, PhD
David Ludwig, MD, PhD

“If people direct their focus on the overall health benefits of the food they eat, instead of the varying nutrients that make up different foods, they’re more likely to increases the amount of healthy nutrients they take in,” says Ludwig. “They’d also be likely to consume fewer calories and lower their risk of chronic disease. Based on growing obesity problem in this country, it seems that decades of nutrient-focused guidelines have done the opposite of that.”

Ludwig says nutrient-based guidelines are scientifically accurate as far as balanced diets are concerned, but aren’t particularly helpful to most people when making food choices. For example, typical recommendations suggest kids consume at least half of their total energy from carbohydrates, and eat anywhere from 10 to 25 grams of fiber and three to six grams of salt daily, depending on their age. Sound advice, but how many of us can accurately gauge our kids’ daily consumption of carbohydrates, fiber or salt, simply based on the type of foods they eat? And even if you can accurately determine the amount of energy they’re getting from carbohydrates, Ludwig points out that foods like brown rice, white bread and apples all qualify as carbohydrates but have very different health effects, so simply feeding your child the right amount of carbs isn’t a guarantee he’s getting a well balanced diet.

Small amounts of nutrients can be added to any food. Being a small part of a balanced diet doesn’t make something healthy.
Small amounts of nutrients can be added to any food. Being a small part of a balanced diet doesn’t make something healthy.

To confuse things further, the food industry “fortifies” highly processed foods like refined cereals and sugar-sweetened beverages with selected micronutrients, and then touts the health benefits of the products. Under the current nutrient-based guidelines, companies can add small amounts of vitamins or minerals to sugar-laden cereals or juices, then print misleading slogans on the packages like: “Contains six essential nutrients recommended by the FDA!”

“The evidence clearly shows the limitations of nutrient-based metrics,” says Ludwig, who suggests that transitioning to a food-based approach—which uses the same nutritional science but provides a more practical approach for the general public—would be extremely beneficial for anyone looking to make more informed food choices for themselves and their families. “It’s time we made it easier for consumers to make healthful eating choices and eliminate misconceptions about what constitutes healthful diets.”