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“Complex carbs are always healthier than simple carbs, right?” Imagine if your client asked you this question.

How would you respond as a certified nutritionist?

While you know the answer isn't a straightforward "yes," you'll likely struggle to explain to your client why complex carbs aren't always synonymous with healthy carbs.

And it isn’t difficult to see why.  

The subject of complex and simple carbs is, well, complex. It’s full of nuances. Whether a carb is complex or simple, its “healthiness” ultimately hinges on several factors, including its overall nutritional composition and degree of processing.

So, how can you word all those nuances in a way your client can easily understand? This article is here to give you a helping hand.

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Simple Carbs vs. Complex Carbs: What's the Difference?

To fully appreciate the intricacies of simple versus complex carbs, your client must first know what carbs are and what they do in the body.

What Are Carbs?

Along with protein and fat, carbohydrates are one of the three macronutrients, which are nutrients the human body needs in large quantities.

The primary function of carbohydrates is to provide energy to all cells in the human body.

During digestion, most carbohydrates—not all; we'll touch on why later—get broken down into single-unit sugars (e.g., glucose, fructose, and galactose), which are absorbed into the bloodstream and transported for use as energy throughout the body.

The Three Types of Carbohydrates

Carbohydrates can be split up into three main types based on their chemical structures.

#1: Sugars

 Sugars are also known as simple carbohydrates.

That's because their chemical structure is simple, being found in the form of monosaccharides (single sugars) or disaccharides (two sugar molecules joined together).

Examples of monosaccharides include glucose, fructose, and galactose, while disaccharides include sucrose, lactose, and maltose. Simple sugars are naturally found in fruits, dairy, and sweeteners like maple syrup and honey.

#2: Starches

Starches are polysaccharides made up of a chain of glucose molecules joined together in covalent bonds.

These large sugar molecules can be found in foods like whole grains, beans, potatoes, and corn.

#3: Fiber

Unlike sugars and starches, dietary fiber—a carbohydrate in plant foods like leafy greens—isn't broken down for energy usage and storage in cells, tissues, and organs.

That's because it's made up of a long chain of sugar molecules bound together in a way that is challenging for the human body to break down and use readily as energy.

Instead, it passes through the body mostly undigested.

But that doesn’t mean dietary fiber is “useless.” There are two types of fiber, and both do a variety of beneficial things for the body.

First up, there’s soluble fiber.

As its name suggests, soluble fiber can dissolve in water. When consumed, soluble fiber swells up with water in the stomach, partially dissolving to form a thick gel-like substance that slows digestion.

This process helps slow down the rate at which digested carbohydrates enter the bloodstream—preventing spikes in blood glucose levels after eating.

Soluble fiber also has a regulatory effect on the absorption of dietary cholesterol.

Specifically, research shows that it could lower the level of LDL cholesterol (i.e., "bad cholesterol") in the blood, potentially reducing the risk of cardiovascular disease.

The second type of dietary fiber is insoluble fiber. It does not dissolve in water.

Instead, insoluble fiber passes right through the digestive tract looking pretty much the way it came in. So, what's the use of that, then? Well, it adds bulk and attracts water into the stool, making it softer and easier to pass.

In other words, it keeps the digestive system healthy.

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Complex and Simple Carbs Differ in Glycemic Response

At this point, your client has likely inferred that:

  • Simple carbohydrates refer to sugars—because they have a “simpler” chemical structure
  • Complex carbohydrates refer to starches and fiber—because they have a more “complex” chemical structure

Now, you and your client can discuss why complex carbohydrates are often thought of as “healthy carbs”—diving into the differences between rates of digestion and the resulting glycemic response:

  • Simple carbs: These small sugar molecules can be broken down and absorbed into the bloodstream quickly, which is why consuming simple carbs is associated with a quick spike in blood glucose levels, closely followed by a sharp decline, thanks to insulin response. Such rapid fluctuations in blood glucose levels are bound to happen occasionally. But repeated, consistent, and uncontrolled dramatic spikes and dips may contribute to insulin resistance and a higher risk of cardiovascular disease.  Insulin resistance occurs when cells in the body don’t respond well to insulin and can’t take up glucose from the blood. 
  • Complex carbs: Thanks to starch’s complex structure, the process of breaking it down into smaller and smaller chunks of sugar molecules until they become “simple” enough for the body to absorb will take more time. They’re absorbed more slowly. So, complex carbohydrates tend to raise blood sugar levels relatively slower and steadier than simple carbs.

Not All Complex Carbs Are “Healthy Carbs”

Simple carbs frequently cause rapid blood glucose spikes and dips. Complex carbs don’t tend to do the same. So, simple carbs equal “bad carbs,” and complex carbs equal “good carbs,” right?

It’s not as simple as that. Not all complex carbs are “healthy carbs.”

To help you illustrate why, ask your client to pick which they think is healthier: A cup of fruit or some potato chips?

Chances are that your client will pick the cup of fruit over the potato chips.

If they can't explain their choice, it's an excellent opportunity for you to reiterate that the "healthiness" of a carb goes beyond whether it's simple or complex. It also depends on two other factors.

Level of Food Processing

The more processed a food is, the more likely it'll be calorie-dense, high in added sugar, saturated fat, and sodium, and lower in fiber. It will also often be stripped of health-beneficial nutrients, including vitamins and minerals.

Take those potato chips, for instance.

They’re packed full of complex carbohydrates—but are they healthy? With the typically added amounts of added sugar, sodium, calories, saturated fats, and trans-fat, it’s safe to say they’re not.

On the other hand, while fruits are filled with simple carbohydrates, they’re also packed with essential vitamins and minerals.

As a rule of thumb, you may find it helpful to guide your client to prioritizing minimally processed types of carbohydrates over more processed ones, like:

  • Unrefined carbohydrates (e.g., brown rice, whole wheat pasta, whole grains, sweet potatoes) over refined carbohydrates (e.g., white rice, chocolate bars, pastries, breakfast cereals)
  • Naturally occurring sugars over table sugar
  • Whole fruits over fruit juice concentrates and canned fruits 

You may also wish to provide your clients with information on how they could make use of nutrition labels and food labels to gain clarity into how processed a certain type of carbohydrate is.

Serving Size

Just because fruits, brown rice, and whole grains are minimally processed carbohydrates doesn't mean your client should eat large amounts in one sitting.

For relatively steady blood glucose levels, your client should ideally limit their carbohydrate consumption to between 50 to 75 grams per meal.

How Should Your Client Manage Their Intake of Carbs?

How many carbohydrates should your client eat? Should they care about carb timing? The answer to all of that is: It depends.

On what? Two things:

  • Is your client on a low, regular, or high-carb diet? According to the U.S. Dietary Guidelines, 45% to 65% of adults’ calories should come from carbohydrates. That said, depending on your client's goals (e.g., are they trying to lose weight, gain weight, or build muscle?) and preferences, they may have decided to lower or increase their carb intake.
  • Does your client work out? If so, you might provide them with info about  timing their simple and complex carbohydrate intake to optimize workout performance and recovery. Eating complex carbs at least two to three hours before they exercise will help them tap into steady, slow-releasing energy when working out. Also, consuming simple carbs from whole foods (e.g., bananas) within 30 to 60 minutes of their workout could help give them a quick energy boost. They may also need to take in more simple carbs during the workout session if it lasts beyond an hour. 

Bottom Line: Complex Carbohydrates Are Not Always Healthier

Hopefully, you now feel more confident helping your clients grasp the subtleties of the differences between simple and complex carbohydrates.

As a certified nutrition coach, tackling the differences between carbs likely isn’t the only potentially confusing topic you’ll have to cover with a client when guiding them toward making healthier choices. So, how can you feel more confident in coaching and sharing your nutritional knowledge?

By continually learning and staying current on the latest updates in the field. And you can do so with AFPA's specialist nutrition programs, like our Holistic Nutritionist Certification, Gut Health Nutrition Specialist Certification, and Plant-Based Nutrition Specialist Certification.

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Article Categories: Food & Nutrition Science
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