Embrace Facts and Reject Fearmongering about Potatoes and Carbohydrates
A recent post in The New York Times—"The Fats You Don't Need to Fear, and the Carbs That You Do"—suggests there are certain sources of carbohydrates that one should be afraid to eat based on their glycemic index (GI). Potatoes, in particular, are cited as a high-GI carbohydrate that "acts like sugar" in the body. This tired hyperbole is based on outdated science and does not reflect the large body of evidence supporting the consumption of potatoes as part of healthy, balanced diet. While the article blames the high GI of certain carbohydrate-rich foods as a reason why they might be associated with weight gain, the GI has been shown to have limited utility in clinical practice given that foods are nearly always eaten as part of a mixed meal. In fact, a recent multi-center human clinical trial published in JAMA concluded that selecting specific foods based on their GI may not improve cardiovascular risk factors or insulin resistance in overweight adults (1). Other research has shown that weight loss diets differing substantially in glycemic load induced comparable long-term weight loss (2). Furthermore, the GI has been rejected repeatedly by several Dietary Guidelines Advisory Committees as the science remains inconclusive about the utility of the concept for policymaking.
Headlines like this one in The New York Times mislead the public and create distrust among consumers. They most certainly do not sensibly guide Americans toward eating a healthy diet that is rich in a wide variety of carbohydrate sources, including fruits, vegetables, whole grains, and legumes. Categorizing foods as "good" or "bad" serves no purpose except to fuel unnecessary stress and guilt. Discouraging potato consumption—the highest source of potassium among commonly consumed vegetables—or vegetable consumption of any kind makes little sense when Americans of all ages woefully under-consume all vegetables, including potatoes. In fact, recent reports have shown that 87% of adults and 93% of children are not meeting current vegetable recommendations, which range from 1.5–3 cups/day based on age and calorie needs (3).
Far from an empty-calorie starch, the white potato is an important source of essential nutrients, including potassium, vitamin C, vitamin B6, dietary fiber, and magnesium. The potato is among the best sources of potassium and fiber—two of the four nutrients of concern established by the Dietary Guidelines for Americans and the National Academy of Medicine (formerly the Institute of Medicine) as being inadequately consumed by adults and children. The potato is also an affordable, versatile vegetable that can be confidently recommended as part of a healthy dietary pattern.
What should a positive, measurable, and achievable message to the public be? Make half your plate fruits and vegetables, and enjoy a variety of vegetables—including potatoes—every day.
(1) Sacks FM, Carey VJ, Anderson CA, Miller ER III, Copeland T, Charleston J, et al. Effects of high vs low glycemic index of dietary carbohydrate on cardiovascular disease risk factors and insulin sensitivity: the OmniCarb randomized clinical trial. JAMA. 2014 Dec 17;312(23):2531-2541.
(2) Das SK, Gilhooly CH, Golden JK, Pittas AG, Fuss PJ, Cheatham RA, et al. Long-term effects of 2 energy-restricted diets differing in glycemic load on dietary adherence, body composition, and metabolism in CALERIE: a 1-y randomized controlled trial. Am J Clin Nutr. 2007 Apr;85(4):1023-1030.
(3) Moore LV, Thompson FE. Adults meeting fruit and vegetable intake recommendations—United States, 2013. MMWR Morb Mortal Wkly Rep. 2015 Jul 10;64(26):709-713.