Carbohydrates and Diabetes

How many carbs should a person with diabetes have?

Carbohydrates are one of the three major macronutrients and one of your body’s primary sources of energy.

If you have diabetes, you’ve probably seen a lot of mixed messages about carbs. For example, you may have heard that you should avoid carbs completely or that you should minimize simple carbs and instead eat complex carbs. 

You may have heard that net carbs are important for people with diabetes or that high-carb diets are ok for diabetes as long as the diet is also low-fat.

Many people associate carbs with bread, pasta, and potatoes and are often surprised to learn that most foods, even vegetables, contain carbs.

Rather than being scared of carbs or trying to avoid them altogether, it’s important to understand how carbs work and the different types of carbohydrates. Different types of carbs affect your body and blood sugar levels differently. Understanding how carbs work is an essential part of managing diabetes.

What Are Carbs?

Carbs is short for carbohydrates – one of the macronutrients found in food. The different types of carbs are starches, sugars, and fiber.


Close up view of man holding wheat in his hands in a field of wheat.Starches are long branch-chained molecules used by plants to store energy. They’re made up of glucose (sugar) units. Starches are quickly broken down into sugar, which is what your body uses for fuel. Starches make up the bulk of cereal grains, such as wheat, rye, barley, corn (maize), and rice. These foods are all rich sources of carbohydrates.

Most foods high in starch generally don’t taste sweet unless they have added sugar. However, once starchy foods are digested, they affect blood sugar the same way as eating pure glucose (sugar) and cause blood sugar levels to rise.


A bottle of honey laying on a table next to a glass jar of honey with a spoon in it. Honey is a sugar and carbohydrate.Sugar is another type of carbohydrate. It is a simple carbohydrate found in plants and animals, especially in fruits, vegetables, honey, and syrups. Some common sugars include glucose, fructose, maltose, and lactose.

Some examples of whole foods that contain sugar are fruit, vegetables, dairy products (milk, yogurt, etc.), and some nuts and seeds.

Added sugar is usually in the form of highly processed corn syrup. However, added sugars can also be from natural sources marketed as “healthier” options. These include honey, agave nectar, maple syrup, etc. Some research has found that your body processes these sugars the same way, regardless of how “healthy” the sugar is.


Foods rich in fiber displayed laying on a table, top view.Fiber is the indigestible part of plants like fruits, vegetables, legumes (beans), and whole grains. Fiber helps prevent constipation by speeding up the digestive process. It also reduces blood cholesterol levels which can reduce your risk of heart disease or stroke.

One of the best things about fiber is that it helps improve blood sugar levels. High-fiber foods, such as whole grains and vegetables, slow down digestion. They also take longer to leave your stomach, which can help you feel fuller for a longer time. Fiber appears to be especially helpful in preventing spikes in blood sugar after a meal.

In his article, Fibre the Anti-Nutrient, Dr. Jason Fung does an excellent job explaining the role of fiber, particularly for people with diabetes.

One study found that only 5% of Americans get enough fiber in their diet. The USDA recommends that adults eat at least 14 grams of fiber for every 1,000 calories they get from their food. For most people, this translates to 22-28 grams of fiber per day. People with diabetes may benefit from increasing this amount to 30-40 grams of fiber per day due to fiber’s many protective health benefits.

Simple Carbs vs. Complex Carbs

Simple carbohydrates are quickly digested. This means they raise your blood sugar quickly and give you a quick burst of energy. However, the energy doesn’t last long because simple carbs digest fast too. People with diabetes, particularly type 1 diabetes and LADA, usually have to take insulin when eating simple carbs to keep their blood sugar from spiking too high.

In contrast, complex carbohydrates digest more slowly. When you eat complex carbs, your body gets sustained energy through longer periods, resulting in fewer risk factors involved in developing diabetes and cardiovascular disease.

Simple Carbs

Foods with simple carbs displayed on a table, top view, bread, sugar, cookies, candy, juice, white pasta.Simple carbs are sugars – glucose, fructose, maltose, and lactose – found in both plants and animals.

Simple carbohydrates are made up of just one or two units (i.e., glucose) and do not need to be broken down into smaller units before being absorbed into the bloodstream. They include common white table sugar, lactose in dairy products, fructose found in fruit juice, honey, and high-fructose corn syrup.

Complex Carbs

Foods with complex carbs displayed on a white background, whole grain bread, sweet potatoes, oats, beans.Complex carbs include starches and fiber and are generally healthier than simple carbs. Complex carbs are long branching molecules of glucose that plants use for energy. This type of carbohydrate is broken down slowly and changes to sugar gradually in the body.

Complex carbohydrates include foods like whole grains, beans, vegetables, and legumes. These foods tend to have a lower glycemic index which means that your blood sugar levels won’t spike as quickly or as high after eating them compared with eating simple sugars. 

Complex carbs are usually rich in fiber, which contributes to their slower digesting properties.

There is a significant difference between eating highly refined starches, such as white bread and white potatoes, versus whole grain and more nutrient-dense starches, such as sprouted whole-grain bread and sweet potatoes. Highly refined starches will raise blood sugar levels quickly, similar to simple carbs.

How Are Carbs Processed?

To better understand carbs, what types of carbs you should eat, and what you should avoid, it is important first to understand how your body processes carbs.

Your body breaks down carbohydrates into glucose (sugar)—the main fuel source for your cells—which raises blood sugar levels. As your blood sugar rises after a meal, your pancreas releases insulin – the hormone responsible for transporting the glucose out of the bloodstream and into muscle cells where your body’s energy needs can use it.

When you have diabetes, your cells are either resistant to insulin (prediabetes and type 2 diabetes), or your pancreas makes little to no insulin (type 1 diabetes and LADA). Because of this, your blood sugar levels may spike quicker than someone without diabetes and take much longer to return to a normal level. Depending on your diet and type of diabetes, you may require injected insulin for blood sugar to return to normal after eating carbohydrates.

When you eat complex carbs, your blood sugar rises slower and returns to normal quicker when compared to eating simple carbs. This is largely due to the fiber in complex carbohydrates. However, it is important to note that all digestible carbs (net carbs), are absorbed by your body and can raise blood sugar.

How Does Your Body Use Carbs?

Your body uses carbs for energy.

Your digestive system breaks down carbs into smaller units of sugar, which are then absorbed into your blood. This causes a rise in blood glucose levels, which is used by your cells as fuel.

If you eat more carbs than your body needs immediately for energy, the excess will be converted to fat and stored in your liver and muscles for future use or to be used during exercise if needed.

As a result, when you eat significantly more carbohydrates than your body needs for immediate energy, your body fat increases.

What Are Net Carbs?

Net carbs refers to the amount of digestible carbs within a food. Remember that fiber is not digestible. To calculate net carbs, you take the total carbs and subtract the fiber.

Net Carbs = Total Carbs – Fiber

Most nutrition labels do not contain a listing for net carbs, which means you will need to calculate this number yourself.

How Do Sugar Alcohols Contribute to Net Carbs?

If you do a Google search for “net carbs,” you’re undoubtedly going to find a few different answers. Some sources will also subtract sugar alcohols from the total carbs since sugar alcohols usually have minimal effect on blood sugar. Sugar alcohols are artificial sweeteners that are created to have no or minimal effect on blood sugar. Some examples of sugar alcohols include erythritol, xylitol, sorbitol, and maltitol.

At Total Diabetes Wellness, we choose to take a more conservative approach and not subtract sugar alcohols. This is because sugar alcohols affect everyone differently. For example, one person might find consuming sugar alcohols has zero effect on their blood sugar, while someone else might find their blood sugar raises slightly.

Benefits of Eating Low-Carb for Diabetes

A low-carb diet offers many benefits, especially for people with diabetes, high blood sugar levels, or people wanting to lose weight.

Doctor measuring a man's waist with a yellow tape measure.

Some of the main benefits of a low-carb lifestyle include:

Learn more about the benefits of a low-carb diet:

The Best Carbs To Eat on a Low-Carb Diet

Many vegetables are low in carbs and also high in fiber, making them ideal for low-carb diets. Vegetables and fruits are also rich in many of the vitamins and minerals your body needs. Nuts and seeds are also nutrient-dense; however, some are higher in carbs and should be eaten in moderation.

Top view of healthy low carb foods - broccoli, avocados, lettuce, spinach, cauliflower

Here are some of the best low-carb foods to eat:

  • Avocados
  • Bell peppers
  • Broccoli
  • Mushrooms
  • Asparagus
  • Cauliflower
  • Zucchini
  • Spinach
  • Brussels sprouts
  • Onions
  • Cabbage
  • Green beans
  • Kale & leafy greens
  • Pecans
  • Macadamia nuts
  • Chia seeds
  • Flax seeds
  • Raspberries
  • Blueberries
  • Blackberries

Learn more about the Best Low-Carb Vegetables:

Different Types of Low-Carb Diets

There are many different types of low-carb diets, but the most common ones are:

  • The Keto Diet
  • The Atkins Diet
  • The Paleo Diet
  • Intermittent Fasting

The keto (or ketogenic) diet is the most restrictive of the different types of low-carb diets. It typically limits you to 20 grams of carbs or less per day, which can be challenging for some people.

The Atkins diet is similar to the keto diet but not as restrictive. It also involves making an initial period of weight loss by severely limiting your carbohydrate intake. After this initial period of healthy weight loss, it allows more carbohydrates than the typical low-carb diet does.

The Paleo Diet emphasizes proteins and vegetables over carbs and sugars. This diet is all about living as our ancestors did in the distant past before grains were mass-produced.

Intermittent fasting (IF) is not an actual “diet” but rather a pattern of eating that involves periods of not eating. There are different types, but common ones include the 16/8 method and 5:2 diet.

How Many Carbs Should You Eat on a Low-Carb Diet?

The USDA recommends adults consume roughly 200-300 grams of carbs per day. Many Americans consume close to double (or more) than this recommendation. Eating such a carb-heavy diet is harmful to your health and contributes to the development of many diseases.

There isn’t a universal definition of what constitutes a low-carb diet. By definition, anything below the USDA recommendation of carbohydrate intake could be considered low-carb.

Total Diabetes Wellness defines a low-carb diet as anything below 100 grams of net carbs per day.

Our low-carb diet recommendations:

  • Your daily net carb intake is between 50-100 grams. This is about 10-30% of your energy derived from carbohydrates.
  • You consume a moderate amount of protein, usually between 80-140 grams per day, depending on your weight and gender. This is about 20-30% of your energy derived from protein.
  • The remainder of your diet is from natural fats. This is about 40-70% of your energy derived from fat.

While a keto diet has excellent benefits for people with diabetes, many people find limiting themselves to only 20 grams of carbs per day too restrictive, and the diet quickly becomes unsustainable.

For this reason, we recommend starting with 50-100 net grams of carbs per day. This higher allowance of cabs will allow you more freedom to include a wider range of foods in your diet, and you won’t feel as restricted. As a result, you will hopefully be able to successfully make a permanent lifestyle change rather than being on a short-term “diet.”

Always discuss diet changes with your doctor BEFORE making changes to your current diet. This is especially important if you are on medications. Full disclaimer here.