Carbohydrates: Good or Bad?


By Becky Bell

There is conflicting information out there about carbs. Studies have shown that low-carb diets are effective for weight loss, but that doesn’t mean that eating carbs makes you fat.

Studies have shown that low-carb diets are effective for weight loss, but that doesn’t mean that eating iStock

In fact, there are plenty of health benefits associated with eating carb-containing foods, but that’s only if you eat the right kinds.

While some high-carb foods are highly nutritious and even helpful for weight management, others are detrimental to your health.

What Are Carbs?

Carbohydrates or carbs, are one of three macronutrients that provide the body with energy. The other two are protein and fat.

There are three major classes of carbs:

  • Sugars: Individual sugar molecules or short chains of sugar molecules. These include glucose, fructose, galactose and sucrose.
  • Starches: Longer chains of carbohydrate molecules that need to be broken down in the digestive system.
  • Fiber: Carbohydrates that the body cannot digest.

The primary function of carbs is to provide the body with energy.

Most carbs are broken down into glucose in the digestive system and provide the body with fuel to perform essential functions.

Each gram of carbs provides the body with four calories. The exception to this is fiber, which generally does not provide many calories.

Bottom Line: Carbohydrates are a macronutrient that provides the body with energy. Carbs include sugars, starches and fiber.

Not All Carbs Are Created Equal

Part of the reason there is so much confusion regarding carbs is that not all carbs are created equal.

People tend to classify all carbs as either good or bad, but that doesn’t make sense.

There are major differences in the health effects of different types of carbs, so they cannot all be lumped into one group.

One way that carbs are classified is by the terms “simple” and “complex.” Some people define all starch and fiber as complex carbs and all sugars as simple carbs.

However, this definition can be confusing. Some starches like sweet potatoes, quinoa and legumes provide many health benefits, while other starches like refined wheat flour are associated with a myriad of health problems.

Additionally, not all sugars have the same effect on your body. Added sugars like those found in baked goods and sugary drinks can harm your health (1, 2, 3, 4).

However, the natural sugars found in fruits and vegetables do not have the same negative effects.

It makes more sense to define complex and simple carbs this way:

  • Complex carbs: Carb-containing foods that are in their whole, unprocessed form. Foods in this category include fruits, vegetables and legumes.
  • Simple carbs: Sugars and starches that have been refined and stripped of their natural fiber and nutrients.

Bottom Line: Complex carbs are healthy, whole foods in their unprocessed form. Simple carbs are refined grains and sugars that have very little nutritional value.

Complex Carbs Are Highly Nutritious, but Simple Carbs Are Not

Complex carbs are healthier than simple carbs because they are generally nutrient dense. This means they contain a large amount of nutrients in relation to the number of calories they provide.

Whole grains, fruits, vegetables and legumes are highly nutritious foods that are rich in antioxidants, fiber, vitamins and minerals.

On the contrary, simple carbs contain “empty” calories, meaning they have calories, but very little nutritional value.

To highlight the nutritional differences between complex and simple carbs, let’s compare whole grains and refined grains.

A whole grain contains three distinct parts:

  • Germ: The seed portion of the grain that’s high in polyunsaturated fats and various important nutrients.
  • Endosperm: The inner portion of the grain that’s mostly made up of starch.
  • Bran: The hard outer portion of the grain that’s high in fiber and essential fatty acids.

The germ and bran of a grain are where the majority of its nutrition is found.

Interestingly, when grains are processed and refined, the highly nutritious germ and bran are removed, leaving only the starchy endosperm.

Below is a comparison of the nutritional content of one cup (120 grams) of whole wheat flour and one cup of refined wheat flour (5, 6):

Whole wheat flour is a source of several important nutrients, but those nutrients are lacking in wheat flour that has been processed and refined.

The same is true for fruits and vegetables. In their whole forms, they contain small amounts of fructose, but they are also packed with vitamins, minerals and fiber.

On the other hand, processed foods and sugary beverages contain large amounts of sugar and absolutely no nutrients. These added sugars are associated with all kinds of health problems (1, 2, 3, 4).

Bottom Line: Complex carbs, such as whole grains, fruits, vegetables and legumes, are highly nutritious. Simple carbs provide calories, but no nutritional value.

Health Benefits of Complex Carbs

Carbs are not essential for life, but eating the right kind may benefit your health.

Complex Carbs Are Less Likely to Cause Blood Sugar Spikes

Simple carbs are digested very quickly, which causes a spike in your blood sugar.

The blood sugar spike stimulates your pancreas to release a large dose of insulin, which often leads to a blood sugar “crash,” leaving you hungry and craving more sugar (7, 8).

Fiber-rich, complex carbs take much longer to break down than simple carbs. This helps keep blood sugar levels steady, as sugar reaches the blood stream gradually (9, 10).

Because complex carbs are digested more slowly, they provide sustained energy and help you feel full for longer (11).

Complex Carbs May Reduce Your Risk of Some Chronic Diseases

Consuming complex carbs may help lower your risk of chronic diseases, such as diabetes and heart disease (12, 13, 14, 15, 16, 17).

They tend to be high in dietary fiber, vitamins, minerals, antioxidants and plant compounds. All of these components play a role in disease prevention (18, 19).

Furthermore, studies have found that eating whole foods high in dietary fiber may lower “bad” LDL cholesterol and blood sugar levels, as well as help raise “good” HDL cholesterol (20, 21, 22).

Complex Carbs Promote a Healthier Digestive System

There are billions of “good” bacteria lining your intestines. They’re known as your gut microbiota.

They play a role in managing several digestive disorders and have been linked to various other aspects of health (22, 23, 24).

Soluble fibers found in complex carbs feed the beneficial bacteria and increase their presence in your gut. They also help the bacteria produce nutrients, such as short-chain fatty acids, which are beneficial for digestive health (23).

Complex Carbs May Reduce Inflammation

Inflammation is the body’s natural response to infection or injury. However, long-term inflammation can increase the risk of several chronic diseases (25).

While sugary foods and refined flours promote inflammation, complex carbs help reduce inflammation (26).

Single-ingredient whole grains, fruits, vegetables and legumes contain fiber and plant compounds that have anti-inflammatory properties (27, 28).

Bottom Line: Complex carbs like whole grains, legumes, fruits and vegetables have multiple health benefits.

Simple Carbs Can Be Detrimental to Your Health

Simple carbs like refined grains and added sugars are horrible for your body.

Below are some of the detrimental health effects of simple carbs:

  • They contribute to overeating: Simple carbs break down quickly and cause a blood sugar roller coaster. Studies have found that these blood sugar spikes and crashes contribute to cravings, hunger and overeating (7, 8, 29).
  • High triglyceride levels: Large amounts of refined carbs can lead to elevated triglyceride levels, which increase the risk of heart disease and type 2 diabetes (3, 30, 31, 32).
  • Increased heart disease risk: Sugar and refined grains increase heart disease risk. A study found those who ate the most refined grains were 2–3 times more likely to develop heart disease than those who ate the least (33, 34, 35, 36, 37).
  • Increased risk of type 2 diabetes: Excessive consumption of simple carbs can cause your cells to become resistant to insulin, which greatly increases your risk of type 2 diabetes (34, 38, 39, 40, 41).
  • Sugar is addictive for some people: Similarly to recreational drugs, sugar causes the brain to release dopamine. For people that are prone to addiction, sugar can be highly addictive (42, 43).
  • Increased chance of becoming obese: Simple carbs harm the hormones that regulate appetite, making them likely to contribute to obesity (29, 44).

Bottom Line: A diet high in refined carbs can have multiple negative health consequences.

Which Foods to Eat and Which Foods to Avoid

Carbs can be a healthy part of your diet if you choose the right ones.

The healthiest carbs are from foods that are in their whole, unprocessed form.

Complex Carbs to Eat

The following foods are good carbs to include in your diet:

  • Whole grains: Whole, unprocessed grains like oats, quinoa, barley and brown rice.
  • Legumes: Lentils, black beans, kidney beans, black-eyed peas, etc.
  • Vegetables: Sweet potatoes, broccoli, green beans, carrots, asparagus, etc.
  • Fruits: Apples, berries, oranges, kiwi, etc.
  • Nuts and seeds: Almonds, walnuts, peanuts, chia seeds, etc.

Refined Carbs to Limit or Avoid

These foods tend to contain mostly refined carbs and should be limited:

  • Sugary beverages: Soft drinks, sweetened tea, sports drinks, fruit juices, etc.
  • Desserts and sweets: Donuts, cakes, cookies, ice cream, candy, etc.
  • White bread: This includes “white wheat” bread.
  • White pastas: These are made from refined wheat flour.

Bottom Line: Complex carbs that are in their whole form are generally healthy foods that are rich in fiber and nutrients.

Take Home Message

Complex carbs are far more nutritious than simple carbs.

They are high in nutrients and fiber and eating them on a regular basis can be beneficial for your health and waistline.

On the other hand, simple carbs provide little to no nutritional value and should be avoided as much as possible.

Reposted with permission from our media associate Authority Nutrition.

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