Dealing with Carbs and Diabetes

Carbohydrates are an important energy source for the body. But carbs can be challenging for people with diabetes because of its impact on blood sugar level. You don’t have to stop eating carbs if you have diabetes but you do have to choose wisely.

In this article, we talk about the carbs that are better for diabetes, how lowering carbs can improve blood sugar and practical ways to reduce your daily carb intake. As always, consult with your diabetes educator or care provider before making major changes to your diet.

What are Carbs?

A carbohydrate is a major source of energy and one of three macronutrients in foods (the other two are protein and fat). 

When we eat food, the body breaks down carbs into sugar which enters the blood. The pancreas then releases insulin, which tells the body to either use the blood sugar for energy or store it in muscles or the liver as glycogen. 

There’s two main kinds of carbohydrates: simple and complex carbs. 

Candies are simple carbs

Simple Carbohydrates

Simple carbs have simple chemical structures that includes either one sugar (monosaccharide) or two sugars (disaccharide). Examples are fructose, table sugar and lactose. 

Because of their simple chemical structure, these carbs are broken down quickly and can lead to blood sugar spikes.

Complex Carbohydrates

Complex carbs have chemical structures with at least three sugars (polysaccharides) and include starches and dietary fibers.  The complex structure means these carbs take longer to digest causing a more gradual increase in blood sugars.

Carbs and Diabetes

Carbs can be challenging for a person managing diabetes. People with diabetes have a condition where their blood sugar exceeds normal levels because the body is not producing enough insulin or isn’t using insulin effectively.

High blood sugar levels over time worsens blood circulation and damages blood vessels, leading to serious health issues. Diabetes medication used to treat this condition is often meant to provide better blood sugar control such as insulin and metformin.

This is why it’s important for people with diabetes to choose their carbs wisely. Foods with high carb content, especially added sugar and refined carbs, makes it harder to keep blood glucose levels within the normal range.

And continuing to have high blood sugar levels can worsen diabetes-related conditions such as insulin resistance, obesity and hypertension.

What are good carbs for a diabetic to eat?

If you decide to eat carbs, choose complex carbs over simple carbs to minimize any increases to your blood sugar level. 

The carbs you eat should also come from whole foods as possible. Many snack foods and processed foods have refined carbohydrates that cause blood sugar levels to spike.

And while mealtime insulin and other medications help control blood sugar levels, simply avoiding refined carbs is just as effective.

Below is a simple guide on choosing carbs for your meal plan.

choosing carbs

Non-starchy Vegetables

Green, leafy or cruciferous vegetables are very low in carbs and good source of fiber. These vegetables are also packed with key nutrients and vitamins. For instance cruciferous vegetables contain glucosinolates, which studies have shown to have anticancer effects.

Broccoli, cauliflower, brussels, kale, mustard greens, and turnips are cruciferous vegetables you find in many groceries. Other non-starchy vegetable options are eggplant, leafy greens, asparagus, cabbage, and beets.

Starchy Vegetables

Starchy veggies that are lower in carbs include squashes, yams, carrots, parsnips, and peas. These are better options than other starchy veggies like potatoes and corn, which have much higher carb contents. 

Butternut squash has only 10 grams of carbs per serving (100g) compared to potatoes which have 20 grams of carbs per serving.

Legumes & Beans

Legumes and beans can be high in carbs so choose wisely. Stick to lower carbs types and not highly processed (e.g. “healthy” snack chips made from bean-derived flours).

brown and yellow beans

Common legumes and beans that are under 30 grams of carbs per serving are green beans, peas, lima beans, lentils, lima beans, black eyed peas, black beans, pinto beans and chickpeas.

What carbs should diabetics avoid?

Grains & Fruit

Because many grains and fruit have high glycemic load, these should make up a small amount of your meal plan. And if you have to eat them choose whole and minimally processed grains and lower carb fruit.  

Real whole grains (i.e. has all three parts of the kernel) have more nutrients and slightly lower glycemic load than processed grains. Real whole grains include whole oats, wild or brown rice, and wheat berries. Quinoa is also an option but it’s actually a seed. 

Fruit with low sugar include berries, avocados, grapefruit, some apples, and kiwi. Fruit that has a moderate amount of sugar are oranges, bananas and some melons.

Refined Sugars

Added sugars, sweeteners and syrups should be avoided as much as possible. These refined sugars are sure to raise blood sugar levels, making it unnecessarily harder to manage diabetes.

Added sugars are found in a lot of packaged foods so pay attention to their food label. Even some products meant for people with diabetes is mostly refined carbs including pre-made nutrition drinks like Glucerna.

How many carbs should a diabetic have a day?

The USDA Dietary Guidelines recommends that carbohydrates make up 45% – 65% of daily calories for adults. However these recommendations are most likely too high for people with diabetes.  These Guidelines apply to the general public – not specifically for people managing diabetes and have high blood sugar levels. 

There is no ideal carb intake amount for people with diabetes because individual situations will vary. But studies continue to show that eating fewer carbs reduces hemoglobin A1C

For instance, this 2018 review of carb restricted eating patterns found that greater carb restriction let to greater reductions in A1C, particularly within 6 months.  And this study comparing a low carb diet to a low fat diet found that low carb eating saw more improvement to A1C. 

While there is no single definition for low carb diets, the studies above defined low carb as making up 26% – 45% of daily calories and very low carb makes up less than 26% daily calories.

Below is a reference table converting calories (%) into to grams of carbs.

This table gives you an idea how many carbohydrates in a day you should be eating. You’ll also need to know the total daily calories your body needs, which you can estimate using online calculators.

How do I lower my carbs?

Now that you know a low carb diet is better for diabetes disease control, there’s a few ways to start limiting carbs in your meal plan.

Carb Counting

A common and accurate way to lower daily carb intake is by carb counting.  Carb counting involves tracking the amount of carbs in each meal and making sure the total carbs consumed in a day is within your daily target. 

sample nutrition label
Image source:

But you’ll need to know how many carbs are in the foods you eat. This can be found in the nutrition food label on packaged foods (pictured right). 

Or if you’re eating whole foods (which you should), you can search online food nutrition databases such as USDA’s database or

When you count carbs, it does take time and effort at first. But don’t worry, it gets easier since you’ll remember the total carbohydrate of many foods you regularly eat.

Modified Plate Method

A simpler (but less accurate) way to reduce carbs is usng a modified version of the diabetes plate method.

The American Diabetes Association plate method starts with a 9” plate and is filled with 50% nonstarchy vegetables, 25% proteins and 25% carbs (which includes grains, legumes and fruit). You can even find food portion tools to help portion your meals.

Our modified plate method (see below) avoids grains and fruit in the carb portion since since the goal is to lower carb intake. Instead, replace with starchy vegetables, legumes or beans.

We also suggest reducing the amount of carbs (%) while increasing other portions.  A good starting point could be a plate with 50% nonstarchy veggies, 35% proteins, and 15% carbs.

We also suggest animal-based protein (over plant-based) in our plate method. Animal based proteins are more energy dense and contain a lot of essential amino acids.

Lean protein is always a safe option but you can also eat proteins with moderate fat, as long as you watch the calories (higher fat = more calories).

Monitor Your Blood Sugar

Regularly monitor blood glucose when you lower carb intake. As blood sugar levels fall your medication may need to be changed and should be discussed with your care provider. For instance, mealtime insulin dose may need to be lowered to prevent blood sugar levels from falling too low.

If you experience very low blood sugar (glucometer reading below 70 mg/dL), quickly eat at least 15g of fast-absorbing carbohydrates. Recheck blood glucose after 15 minutes to see if it’s above 70 mg/dL.

Repeat this until readings are above 70 mg/dL and then eat a meal or complex carb to keep blood sugar from dipping.

Don’t Forget About Your Energy

Count carbs but don’t forget about counting calories too. Lowering your calories from carbohydrates can make you feel less energetic.

Make sure you get enough calories (energy) from protein and fat, especially if you’re staying active. Remember, carbs and protein have 4 calories per gram while fat has 9 calories per gram.


Carbs are an important energy source but can be problematic for people with diabetes. because it raises blood sugar, especially added sugar found in a lot of food today.

Managing diabetes doesn’t stop you from eating carbs but you do have to choose wisely. We talked about how choosing complex carbs and lowering carb intake can greatly improve blood sugar levels. And we showed ways to reduce daily carb intake by carb counting or using a modified version of the plate method.

Keep your meal plan simple! No need to worry if your meals fit into labels like “low carb diets” or the “ketogenic diet.” Just focus on eating fewer calories from carbohydrates and whole, minimally processed foods.

Lastly, staying active and exercise is important for long-term diabetes management. A healthy diet combined with active living will promote weight loss and improve other diabetes-related conditions.

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