7.2: Macronutrients

Carbohydrates (Starch, Fiber, and Sugar)

A carbohydrate is a molecule containing carbon, hydrogen, and oxygen. Carbohydrates are commonly referred to as carbs. They are one of the main types of nutrients and they are the most important source of energy for your body.

For each gram of carbohydrate we consume, we are provided with 4 calories. This is less than half of the Calories provided by one gram of fat! Carbohydrates are the primary energy source for the body’s cells, tissues, and organs (such as the brain and muscles).

When we eat carbohydrates, our body breaks them down into glucose. Glucose then enters our blood stream and is readily available to provide energy to the body both to fuel the brain and nervous system and provide quick energy for exercising. If glucose in the blood, often called blood sugar, is not immediately used, it is stored in the liver and muscles for later use.

On your food label you will see the total carbohydrate intake, which is further broken down into fiber and sugar intake. Carbohydrates are made up of three components: fiber, starch, and sugars. Carbohydrates are present in food in the form of sugar, starch, or fiber. Carbohydrates can be simple (i.e., monosaccharide meaning a single sugar molecule) or complex (i.e., polysaccharide meaning a chain of sugar molecules). Fiber and starch are considered complex carbohydrates and sugar is a simple carbohydrate. Complex carbohydrates have more nutrients than simple carbohydrates and are better for your health. Complex carbohydrates are higher in fiber, so they digest more slowly, and keep us feeling fuller for a longer period of time.

Here are some examples of the types of carbohydrates in foods:

• Simple Carbohydrates: Candy, carbonated beverages, corn syrup, fruit juice, honey, table sugar
• Complex Carbohydrates: Apples, broccoli, lentils, spinach, unrefined whole grains, brown rice
• Starches: Potatoes, chickpeas, pasta, and wheat
• Fiber:
  • Insoluble: Brans, seeds, vegetables, brown rice, potato skins
  • Soluble: Freshly fruit, oat, broccoli, and dried beans

The Role of Fiber in Your Health

We need fiber in our diet! Dietary fiber supports our bowel movements, lowers blood glucose and cholesterol levels, and reduces calorie intake. Unfortunately, more than 90 percent of women and 97 percent of men do not meet recommended intakes for dietary fiber. More than 85 percent of adults do not meet the recommended intakes of fruits, vegetables, and whole grains which would provide them with fiber. In addition, they eat a high amount of processed (refined) carbohydrates which reduce the natural fiber content.

A dietary fiber is a type of carbohydrate that cannot be broken down in the body; therefore, dietary fiber does not provide energy in the form of calories. However, consumption of dietary fiber is important for optimal gastrointestinal health, blood sugar and cholesterol control, and healthy weight maintenance.

Figure \(\PageIndex{1}\): Importance of Fiber

Soluble and Insoluble Fiber

Fiber is commonly classified as soluble, which dissolves in water, or insoluble, which doesn’t dissolve. Soluble fiber dissolves in water to form a gel-like material. It can help lower blood cholesterol and glucose levels. Soluble fiber is found in oats, barley, nuts, seeds, beans, lentils, peas, and some fruits and vegetables. Insoluble fiber promotes the movement of material through your digestive system and adds bulk to the stool, so it can be of benefit to those who struggle with constipation or irregular stools. Insoluble fiber is found in foods such as wheat bran, vegetables, and whole grains.

Refined (Processed) versus Unrefined Carbohydrates

Refined grains are foods that have been processed to remove parts of the grains, which then also removes some of the nutrients that are good for your health. For example, do you choose to eat white rice or brown rice? White rice begins as brown rice and then it gets processed (refined) to remove the risk’s husk, bran, and germ. When this happens, it removes important nutrients such as fiber, vitamins, and minerals. People sometimes refer to refined carbs as empty carbs or empty calories. The body processes refined carbs quickly, so they do not provide lasting energy, and they can cause a person’s blood sugar to spike. Sometimes the white rice is “enriched” whereby fiber, vitamins, and minerals are added back into the rice.

To increase your fiber intake, choose whole grains that have not been refined (processed). To figure out whether a product has a lot of whole grain, check the ingredients list on the package and see if a whole grain is one of the first few items listed. You can also reference the Current Dietary Guidelines.

The Role of Sugar in Your Health

When looking at the food label you will notice data for total sugar and added sugars. Including added sugars was a part of the update to the new food labels. Previous to this update, only total sugar was included. The difference in the two numbers is the source of the sugar, whether it is a naturally occurring sugar or sugar that has been added. Most Americans exceed the recommended limits for added sugars in the diet. There is evidence that diets low in sugar are associated with a reduced risk of developing cardiovascular disease and diets higher in all sugars can increase the risk of developing cavities.

Natural Sugar versus Added Sugar

There are sugars that naturally present themselves in foods and sugars that are added to foods. Below are some examples of both. Sugars naturally present in food include:

• Dairy products (such as milk and yogurt)
• Fruit (fresh, frozen, dried, and canned in 100% fruit juice)
• 100% fruit and vegetable juice
• Vegetables

Added sugars include:

• Baked goods (such as cakes, cookies, pastries, and pies)
• Desserts (such as ice cream and puddings)
• Salad dressings, sauces, spreads, condiments, and gravies
• Sugar-sweetened beverages (such as energy drinks, fruit drinks, soft drinks, sports drinks, and sweetened coffee and tea)
• Sweets (such as candies, jams, sweet toppings, and syrups)
• Single-ingredient sugars (such as table sugar, maple syrup, or honey)

Tips for Consuming Carbohydrates

Here are some tips for consuming carbohydrates:

• Use the food label to understand whether the food you are consuming is considered high or low based on the Percent Daily Value. Note the total Percent Daily Value for carbohydrates, which will help you meet the Acceptable Macronutrient Distribution Range (AMDR) for carbohydrates. That is to consume between 45-65% of your calories from carbohydrates.
• Eat more whole grains (such as brown rice, bulgur, couscous, and quinoa) and choose whole grain versions of common carbohydrates such as breads, cereals, pasta, and rice.
• Look for options that are lower in added sugars, saturated fats, and/or sodium, such as: bread instead of croissants; English muffins instead of biscuits; and plain popcorn instead of buttered.
• Choose whole fruit (fresh, frozen, dried, and canned in 100% fruit juice) as snacks and desserts and use fruit to top foods like cereal, yogurt, oatmeal, and pancakes.
• Keep raw, cut-up vegetables handy for quick snacks. Choose colorful dark green, orange, and red vegetables (such as broccoli florets, carrots, and red peppers).
• Add beans and peas or unsalted nuts and seeds to salads, soups, and side dishes. These are great sources of dietary fiber and protein.
• Try unsweetened or no-sugar added versions of fruit sauces (such as applesauce) and plain, fat-free or 1% low-fat yogurt.
• More often, choose beverages such as water and fat-free or 1% low-fat milk. Less often, choose beverages that are high in calories but have few or no beneficial nutrients, such as energy drinks, fruit drinks, soft drinks, and sport drinks.
• Consume smaller portions of foods and beverages that are higher in added sugars or consume them less often.