Why nutrition advice changes

Americans are bombarded with information about "healthy eating," but we suffer from higher rates of obesity and chronic disease than ever before. We are told one year to avoid fat and the next to avoid carbohydrates. It is enough to make anyone distrust nutritional advice altogether, particularly anything that claims that "food is medicine."

And in many ways, we don't really need much advice because we already know basically what we should do: eat a variety of foods, especially whole grains, fruits, and vegetables; minimize candy, soda and other empty calories; and watch how much we eat. And of course do some physical activity each day.

Then why do we have all the complicated nutritional advice, contradictory research studies, and endless health diets? In part because they give the food companies a way to sell more products. And on our side of the table, it is often easier to read about what we should do, then actually change our eating patterns. As a result, our Standard American Diet (SAD) is not contributing to our health.

The media coverage, which leaps to publicize the latest study, contributes to the confusion. Unfortunately the news stories don't usually investigate the limitations of the research or explain the complexity of the findings. Below are two keys reasons why the results of nutrition research can be flawed or misunderstood.