Starch is a complex carbohydrate and a natural component of many plants, such as fruits, vegetables, and grains. Starchy foods form an essential part of a healthy diet.

When people hear the word “starch,” they may think of foods rich in carbs, such as potatoes, rice, and pasta. However, most plants store energy as starch, including fruits and vegetables.

Starchy foods are the primary source of carbohydrates for most people. They play a crucial role in a nutritious, well-balanced diet, as they provide the body with glucose, which is the main energy source for every cell. They also provide a range of vitamins, minerals, fiber, and other nutrients.

Foods rich in starch are valuable ingredients in the kitchen, too, as they can thicken soups and sauces without adding fat.

Keep reading to learn more about starch, including the types, the health benefits, and the risks of overeating starchy foods.

Field of wheat, a source of starchShare on Pinterest
Erik Isakson/Getty Images

Starch, or amylum, is a complex carbohydrate that exists in many foods, including grains, vegetables, and fruits. The principal sources of starch are:

The extraction of pure starch from food produces a white, tasteless, and odorless powder that does not dissolve in cold water or alcohol.

Starch is a natural polymer, or polysaccharide, meaning that it is a long chain comprising one type of molecule. Starch consists of glucose molecules. It can occur in two forms: amylose and amylopectin.

Amylose is a linear or straight-line polymer that scientists describe as amorphous or solid. Amylopectin forms a branched chain and is crystalline.

Different plants contain varying ratios of these polysaccharide units. However, amylose generally makes up a maximum of 30% of starch, with the rest being amylopectin.

Plants create these starch polymers to store the glucose they create during photosynthesis. For this reason, foods that are rich in starch are good sources of energy.

When someone eats food containing starch, the body breaks down the natural polymers into units of glucose, which provide energy throughout the body.

Besides being part of a nutritious diet, various industries — including pharmaceutical, paper, and food — use starch in their manufacturing processes.

Depending on its nutritional characteristics, starch fits into one of three groups:

  • Rapidly digestible starch (RDS): This form of starch exists in cooked foods, such as potatoes and bread. The body rapidly converts it to glucose.
  • Slowly digestible starch (SDS): This starch has a complex structure, meaning that the body breaks it down slowly. It exists in cereal grains.
  • Resistant starch (RS): The body cannot easily digest this form of starch, and it can pass through the digestive system untouched, similar to dietary fiber. It may support healthy intestinal microflora. Experts further divide RS into four categories, including:
    • RS1, which exists in grains, seeds, and beans.
    • RS2 from raw potatoes and unripe bananas.
    • RS3 from foods that undergo cooking then cooling, such as rice and cornflakes.
    • RS4, which is in bread.

Any given food type can contain various types of these starches.

People can buy different forms of starch to use in cooking, including:

  • Potato: Raw, crushed potatoes are the source of potato starch. The liquid starch dries to form a white, flour-like powder. It is gluten-free and features in various recipes as a wheat flour alternative.
  • Tapioca: This versatile flour comes from the crushed pulp of the cassava root. People can mix it into baked goods or use it as a thickening agent for soups, stews, and sauces.
  • Corn: This starch comes from the maize grain. It can thicken recipes and is a base for corn syrup. Doctors also use it to supply glucose to individuals with glycogen storage disease.

Additionally, modified starch exists, which is a starch derivative that manufacturers have treated to change its properties. The baking industry widely uses this form of starch because it can tolerate a range of conditions, including extreme heat or cold.

Doctors recommend eating plenty of starchy foods as part of a balanced diet to provide energy and fiber, as well as to increase feelings of fullness.


Starch is the most important energy source for humans. The body digests starch by metabolizing it into glucose, which passes into the bloodstream and circulates the body. Glucose fuels virtually every cell, tissue, and organ in the body. If there is excess glucose, the liver stores it as glycogen.

Glucose is essential for brain function. An adult’s brain is responsible for 20–25% of the body’s glucose consumption.

Learn more about high energy foods here.


Dietary fiber is a nondigestible carbohydrate that only exists in plant-based foods. Foods rich in starch, such as corn, beets, potatoes, beans, fruits, and whole grains, are abundant fiber sources. Although the body does not digest fiber, this carb is an essential part of a nutritious diet.

Nutritionists divide fiber into soluble and insoluble forms. Fruits and vegetables are sources of soluble fiber that can absorb water. Soluble fiber feeds the good bacteria in the gut, helps slow digestion, and softens the stool.

Insoluble fiber does not absorb water. Instead, it passes through the digestive system, adding bulk to keep bowel movements regular and prevent constipation. Whole grain foods, nuts, seeds, and leafy green vegetables are good sources of insoluble fiber.

According to the Food and Drug Administration (FDA), most individuals in the United States do not eat enough fiber. Government guidelines suggest that adult females need up to 28 grams (g) of fiber per day while adult males need up to 34 g.

Learn more about high fiber foods here.


Eating starchy foods may help increase satiety, which is the feeling of being full, after eating.

Research shows that eating foods rich in resistant starch helps people feel full. These foods may also improve insulin sensitivity and reduce fat storage. In addition, eating fibrous foods rich in resistant starch may help people maintain a moderate weight.

In a small 2018 study, researchers offered participants breakfast and lunch with either 48 g of resistant starch or a placebo. The participants were then allowed to eat as much as they liked at dinner. The researchers found that consuming the resistant starch at breakfast and lunch significantly reduced the participants’ energy intake during this later meal.

Learn more about foods that may improve the feeling of fullness.

For most individuals, starch does not present any risks or side effects. Nutritional guidelines recommend that people eat a balanced diet that includes starchy foods.

However, people with certain health conditions, including diabetes and congenital sucrase-isomaltase deficiency (CSID), need to moderate their starch intake.

The American Diabetes Association recommends that individuals with type 1 diabetes count how many grams of carbs they eat, then balance this with their insulin dose. Individuals with type 2 diabetes should avoid consuming large quantities of carbs in one sitting and spread them evenly throughout the day instead.

Individuals with CSID will need to follow a special diet. People with this genetic condition cannot digest certain sugars, so they will experience digestive problems if they eat certain fruits, juices, and grains. These issues can lead to malnutrition.

Starch is a carbohydrate and a natural component of most plants, including fruits, vegetables, and grains. Starchy foods are an essential part of a balanced diet, as they provide energy, fiber, and a sense of fullness.

The body breaks down starch molecules into glucose, which is the body’s primary fuel source. The brain, in particular, requires a considerable amount of glucose each day.

Starchy foods are safe for most individuals and present no risks or side effects. However, it is important that people with diabetes or CSID carefully consider their starch intake.