Because potatoes are high in carbs, they have developed a reputation for leading to weight gain and haven been associated with an increased risk for type 2 diabetes. They are often found on lists of foods to avoid, especially for individuals with insulin resistance. However, a new study published in peer-reviewed medical publication Journal of Medicinal Food found that potatoes actually did not increase type 2 diabetes risk and are packed with key nutrients and health benefits.
The study from Pennington Biomedical Research Center examined how a diet that includes potatoes affects key health measures. “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,” Candida Rebello, PhD, an assistant professor at Pennington Biomedical and co-investigator of the study, said in a statement.
The study involved 36 participants between the ages of 18 and 60 who were overweight, obese, or had 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. Both diets were high in fruit and vegetables and substituted an estimated 40 percent of typical meat consumption with either beans and peas or potatoes.
“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,” Rebello explained.
“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,” Rebello pointed out.
Replacing meat with potatoes and beans
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 served together with sides such as mashed potatoes, oven-roasted potato wedges, potato salad, and scalloped potatoes with lunch and dinner entrées.
“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.”
The study helped to identify the impact of potatoes on our metabolism and adds to a growing body of research on obesity and type 2 diabetes. John Kirwan, PhD, principal investigator on the study and Executive Director of Pennington Biomedical Research Center, explains that this research is just one step toward better understanding obesity.
“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,” Kirwan said in a statement. “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.”
Potato protein helps build muscle
Potatoes have additional health benefits beyond improving metabolism and glucose levels. A study published earlier this year in the scientific journal Medicine & Science in Sports & Exercise found that potato protein can be as effective as animal-derived milk in building muscle.
The study hypothesized that because potato protein and animal milk protein share a very similar amino acid composition that both might have a similar effect on muscle protein synthesis, or the body’s way of making amino acids into skeletal muscle protein.
In a double-blind study that consisted of 24 healthy males, the researchers found both protein sources to be comparable. “Ingestion of 30 grams of potato protein concentrate increases muscle protein synthesis rates at rest and during recovery from exercise in healthy, young males,” the study concluded. “Muscle protein synthesis rates following the ingestion of 30 grams of potato protein do not differ from rates observed after ingesting an equivalent amount of milk protein.”