How Do I Tell the Difference Between a Good Carb and Not-so-good Carb?

4 minutes read

Carbs (aka carbohydrates) are macronutrients found in sugar and starchy foods. Think: bread, potatoes, legumes, pasta, and fruit.[1] The primary role of carbs is to provide us with energy—especially during exercise.[2] Our bodies convert carbs into glucose,[1] which can either be expended as energy or stored as fat. 

If we’re consuming more carbs than we’re expending, over time, that excess can lead to an increased risk of insulin resistance, metabolic syndrome, and diabetes.[1] These risks are why low-carb (and even no-carb) diets—like keto and Atkins—consistently make headlines. And while there may be exceptions, generally speaking, carbs are an important part of our diet. 

A recent study by Harvard T.H. Chan School of Public Health shows that consuming a moderate amount of carbs (50–55% of your daily calories) is healthier than both low-carb diets (40% or less) and high-carb diets (70% or more).[4] 

What’s even more important than the amount of carbs you’re consuming is the type of carbs you’re consuming. There are two main types of carbs: complex & simple (refined).

Now, we’re not gonna sit here and tell you that certain carbs are innately “good” or “bad” because the answer is a little more complicated than that—and using absolutes when it comes to food isn’t all that helpful (unless you’ve got an allergy or another medical reason to avoid something completely). So, let’s replace “bad” with “not-so-good” and dig into how our body responds to certain types of carbs.

“Good” carbs: complex

These take longer for your body to break down into glucose (when compared to simple/refined carbs) and often contain other nutrients that your body needs. Notably, they contain starch and fiber, and it’s the fiber content that really helps support a healthy glucose response.  

Examples of complex carbs:

  • Beans/legumes
  • Oats
  • Grains (whole wheat, quinoa, brown rice, etc.)
  • Potatoes/sweet potatoes
  • Vegetables (peas, carrots, broccoli, etc.)

“Not-so-good” carbs: simple or refined 

These are typically considered sugar and can be naturally occurring or food and drinks made with processed sugar. They’re a lot more likely to cause spikes in blood sugar because your body breaks them down faster, and they may contain no extra nutritional value.

Examples of simple/refined carbs:

  • Sugars
  • Syrup 
  • Refined grains (white flour, white rice)
  • Processed foods (breakfast cereal, candy, desserts)
  • Sweetened beverages 
  • Fruit juice 

The above list is a bunch of processed foods/beverages, which is why simple/refined carbs are often considered “bad.” However, it’s not the full picture. Even some foods you might consider “healthy”—fresh, whole foods you might find at a farmers market—fall into the category of simple/refined carbs. These include:

  • Fruit
  • Some vegetables (less fibrous ones)
  • Milk/dairy products 

Again, moderation is key. So, even though simple/refined carbs aren’t necessarily “good” for you, a little bit here and there isn’t the end of the world. And there are even a few “hacks” to help your body better process these (check out this blog for more info)!

Get personal: learn how carbs affect your body

Because carbs contain sugar (even the “good” kind), they can all have an effect on your blood sugar/glucose levels. And this effect will vary from person to person—based on factors like age, sex, body composition, activity levels, metabolic health, overall wellness, and lifestyle factors like sleep and stress.

How do we know how much of an effect the carbs we eat are having on our body? One way is to pay attention to how you feel after eating carbs:

  • Are you energized or tired?
  • Are you comfortable or bloated?
  • Are you satiated and content for a while, or are you craving food/sugar within an hour or two?

The next step is to look at the data. Continuous glucose monitoring (CGM) systems—like the Veri app—help you visualize in real time how foods affect your blood sugar and metabolic health. Over time, you’ll get to pick up on trends and can use those to make highly impactful changes to your diet and lifestyle. Veri helps you discover what eating healthy means for you, personally, because wellness is so individualized. And we’re all done with one-size-fits-all.


  1. David S Ludwig et al., “Dietary carbohydrates: role of quality and quantity in chronic disease”, 2018. Published in The BMJ. URL:  
  2. P D Gollnick, H Matoba, “Role of carbohydrate in exercise”, 1984. URL: 
  3. Meagan Bridges, RD, “Complex carbohydrates”, 2020. URL: 
  4. Sara B Seidelmann, MD et al., “Dietary carbohydrate intake and mortality: a prospective cohort study and meta-analysis”, 2018. Published in The Lancet. URL:

Written by: The Veri Team
Reviewed by:

Table of Contents

  • “Good” carbs: complex
  • “Not-so-good” carbs: simple or refined
  • Get personal: learn how carbs affect your body


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