Not all starchy foods are created equal.
Foods like potatoes and slightly unripe bananas contain resistant starches, which have a number of health benefits with no known harmful side effects.
According to a 2017 study from the British Science Foundation, these starches may help people eat less, as well as improve gut health and blood glucose control.
A 2022 review analyzing the effect of resistant starches on adults with both prediabetes and diabetes also cautiously touts their benefits when it comes to gut health and glucose management but states that more studies must be done before any conclusions can be made.
Starchy foods are foods that are high in carbohydrates, like:
These foods are an important part of a nutritious diet. They’re a good source of energy for the body and typically contain a range of nutrients like fiber, iron, calcium, and B vitamins.
Once consumed, starchy foods break down quickly into sugar that the body can use right away for energy.
Foods containing resistant starches do not break down quickly into sugar in the body. Like fiber, resistant starches tend to travel through the digestive system without a lot of change, helping create beneficial gut bacteria.
Examples of foods high in resistant starch include:
- dried peas
- green bananas
Resistant starch can also form naturally, like when starchy foods like potatoes and pasta are cooked and then cooled.
As stated above, resistant starch is not digested in the small intestine.
Instead, it’s fermented in the large intestine, producing short fatty acid chains and becoming, in essence, a form of fiber.
Those acid chains act as an energy source for colonic cells.
The increase in fatty acids in the colon may help prevent the development of abnormal cells in the gut.
Stacey Lockyer, a nutrition scientist at the British Science Foundation, explains that their 2017 study illustrated “consistent evidence that the consumption of resistant starch in place of digestible carbohydrates can aid blood glucose control.”
This interaction could have a potential benefit for people with type 2 diabetes.
In addition, Lockyer said, there’s evidence that resistant starch may improve gut health and reduce post-meal hunger by stimulating the release of gut hormones that suppress appetite.
Regular consumption of foods high in resistant starch, along with plenty of fruits, vegetables, and nuts, can improve health.
“We know that adequate intake of dietary fiber overall is important for achieving a healthy, balanced diet and reduces the risk of developing a range of chronic diseases including colon cancer, type 2 diabetes, and heart disease,” Lockyer said.
The importance of nutritional balance
Susan Weiner, a registered dietitian and nutritionist, notes that the benefits of resistant starches is a topic that tends to come and go in the health world.
While Weiner did say the benefits touted in the foundation report are backed up by some scientific evidence, she believes more research is needed when it comes to the connection between resistant starch, weight loss, and glucose. According to the 2022 review in Frontiers in Nutrition, she’s right on the mark.
While the authors of that review did find differences in inflammatory markers and glucose levels in individuals with higher resistant starch intake, the variations in the studies involved in the review — especially when it comes to study size, study duration, and dosage — make it difficult to say with confidence that resistance starch can help individuals better manage their glucose.
There’s evidence that resistant starches can suppress appetite, Weiner went on to say, but she noted people still have to become adept at listening to their bodies when they’re full.
They also need to eat nutritious side dishes like vegetables and fruits.
“Everything has to fit together,” she said.
Whether you increase your intake of resistant starches or not, Weiner has some advice for people who are embarking on a new health journey.
Personally, Weiner advises her clients to make specific goals instead of broad objectives.
Goals like “losing weight,” “going to the gym more,” or “being healthier” are too general.
Weiner said choosing one specific goal is a better way to approach weight management.
Goals like drinking water instead of soda or eating one vegetarian meal a week are more helpful and more doable.
“Make one simple change at a time,” she suggested.
Weiner added that it’s better to decide what you’re going to do “more of” instead of what you’ll do “less of.”
“It’s not only what you’re taking out of a nutrition plan — it’s also what you’re putting in,” she said.