Potatoes, long maligned for their carbohydrate content and association with weight gain, are being re-evaluated by nutrition experts who emphasize their status as a healthy whole food. Recent years have seen a decline in fresh potato consumption in the United States, with a shift towards processed potato products like French fries and tater tots.
Nutritionists highlight that potatoes offer a range of essential nutrients beyond carbohydrates. Toby Smithson, a registered dietitian nutritionist and senior manager of Nutrition and Wellness at the American Diabetes Association, notes that potatoes are a rich source of vitamin C, vitamin B6, potassium, and fiber, particularly when the skin is consumed. She added that potassium is crucial for heart health and maintaining healthy blood pressure, and potatoes are a leading source of this mineral among common fruits and vegetables. Barbara Ruhs, an RD, also pointed out that potatoes provide a good quality carbohydrate and a small amount of plant protein.
While potatoes are recognized for their starch content and can affect blood sugar levels, their impact is nuanced and depends on preparation and consumption context. The Glycemic Index (GI) measures how quickly foods raise blood sugar. For example, a plain baked Russet potato has a high GI of 111, while a boiled white potato scores 82. However, waxy potatoes like New Potatoes, especially with skins, have a lower GI. Importantly, the GI of a potato can be significantly altered by how it's cooked and what it's eaten with.
Cooking methods and cooling play a significant role. Carolyn O’Neil, RDN, explained the phenomenon of resistant starch, which increases when potatoes are cooked and then cooled. A potato that has a GI of 82 when hot may have a GI of 49 after being cooked and refrigerated overnight. This resistant starch helps to blunt the glycemic effect. Even reheating chilled potatoes does not negate this benefit. Furthermore, when potatoes are part of a meal, their GI is further moderated. For instance, adding fats and acids, as in potato salad, can lower the GI to approximately 45. Topping a high-GI baked potato with cheese can reduce its GI to 39.
Experts also affirm that potatoes can be incorporated into a balanced diet for individuals with diabetes. Smithson stated that potatoes are a quality carbohydrate that fits within the recommended carbohydrate portions of the Diabetes Plate method. Potatoes provide approximately 3 grams of protein per serving and are rich in both soluble and insoluble fiber. The skin contains insoluble fiber, aiding gut motility, while the flesh contains soluble fiber, which can help slow glucose absorption and manage cholesterol levels.
For endurance athletes, potatoes have also been found to be an effective fuel source. A 2019 study indicated that Russet potatoes are as effective as commercial carbohydrate gels for fueling prolonged physical activity. Nutritionists recommend boiling and chilling potatoes, consuming them with healthy fats and acids, and opting for New Potatoes when appropriate to manage their glycemic impact.