Potatoes can be part of a healthy diet

When we think of healthy vegetables, we don't think of potatoes, but we should. Potatoes have developed a reputation for causing weight gain and an increased risk for type 2 diabetes, and often find themselves on a list of foods to avoid, especially for individuals with insulin resistance. However, a new study from Pennington Biomedical Research Center, published in the Journal of Medicinal Food, says that potatoes actually did not increase that risk, are filled with key nutrients, and packed with health benefits.

Candida Rebello, Ph.D., an assistant professor at Pennington Biomedical, served as co-investigator of the study which examined how a diet including potatoes affects key health measures. Rebello, who is also a registered dietitian, said, "We demonstrated that contrary to common belief, potatoes do not negatively impact blood glucose levels. In fact, the individuals who participated in our study lost weight."

"People tend to eat the same weight of food regardless of calorie content in order to feel full," Rebello explained.

"By eating foods with a heavier weight that are low in calories, you can easily reduce the number of calories you consume. The key aspect of our study is that we did not reduce the portion size of meals but lowered their caloric content by including potatoes. Each participant's meal was tailored to their personalized caloric needs, yet by replacing some meat content with potato, participants found themselves fuller, quicker, and often did not even finish their meal. In effect, you can lose weight with little effort."

The study involved 36 participants between the ages of 18 and 60 who were overweight, had obesity, or insulin resistance. Insulin resistance refers to a health condition in which the body's cells do not respond well to insulin and glucose does not enter into the cells to make energy. Insulin resistance is linked to obesity, high blood pressure, high cholesterol, and type 2 diabetes

Participants were fed precisely-controlled diets of widely available common foods including either beans, peas, and meat or fish, or white potatoes with meat or fish. Both diets were high in fruit and vegetable content and substituted an estimated 40% of typical meat consumption with either beans and peas or potatoes. Previous studies have shown that eating beans and peas improves blood glucose levels in individuals with newly diagnosed type 2 diabetes.

To increase the dietary fiber component of the potatoes, they were boiled with the skin intact and then refrigerated between 12 and 24 hours. Potatoes were incorporated into the main lunch and dinner entrées, such as shepherd's pie and creamy shrimp and potatoes, and served together with sides such as mashed potatoes, oven-roasted potato wedges, potato salad, and scalloped potatoes with lunch and dinner entrees.

"We prepared the potatoes in a way that would maximize their fiber content. When we compared a diet with potatoes to a diet with beans and peas, we found them to be equal in terms of health benefits," Rebello said. "People typically do not stick with a diet they don't like or isn't varied enough. The meal plans provided a variety of dishes, and we showed that a healthy eating plan can have varied options for individuals striving to eat healthy. In addition, potatoes are a fairly inexpensive vegetable to incorporate into a diet."

Pennington Biomedical Research Center's Executive Director John Kirwan, Ph.D., and Principal Investigator on the study said, "Obesity is an incredibly complex disease that Pennington Biomedical is tackling on three different fronts: research that looks at how and why our bodies react the way they do, research that looks at individual responses to diet and physical activity, and policy-level discussions and community programs that bring our research into strategies our local and global communities can use to live healthier lives."

"These new data on the impact of potatoes on our metabolism is an exciting addition to the arsenal of evidence we have to do just that."