People with diabetes are frequently told to avoid eating potatoes and other starchy vegetables because of the perception that these foods make it difficult to control blood glucose levels. However, when consumed in the context of a well-planned meal, starchy vegetables can safely be part of the diet for people with diabetes.
As the name implies, starchy vegetables contain starch, a type of carbohydrate made from sugar molecules which are linked together in long chains. During digestion, starches are broken down and converted to glucose. The more carbohydrate-containing foods you eat at a meal, the more glucose will enter the bloodstream. Now, don’t misunderstand: This does not mean that you should avoid starchy vegetables. But you will need to monitor your portions and consider the combination of other foods on your plate.
Starchy vegetables such as beans, peas and lentils are packed with nutrients. They are excellent plant protein sources and provide other nutrients such as potassium, iron and zinc. Eating more beans, peas and lentils as part of a healthy diet can help lower blood glucose, blood pressure, heart rate and other heart disease and diabetes risks. A study published in the Archives of Internal Medicine found that people with type 2 diabetes who ate one cup of beans, chickpeas or lentils daily had improved blood glucose control, reduced blood pressure and lower cholesterol levels.
The fiber in beans, peas and lentils slows starch conversion into glucose, which keeps blood glucose levels more stable. Many starchy vegetables contain resistant starch—a type of carbohydrate that resists digestion and doesn’t increase glucose levels. Plantains, green bananas, taro root, beans, peas, lentils and white potatoes all have resistant starch. In clinical studies, vegetables with resistant starch have been shown to stabilize blood glucose levels.
It’s important to be aware that the amount of resistant starch in foods changes with heat. For example, green bananas and plantains lose some of their resistant starch when cooked. On the other hand, a cooked white potato that is cooled is higher in resistant starch.