Why should you count carbs?
Figuring out how many carbs to eat when you have diabetes can seem confusing.
Dietary guidelines from around the globe traditionally recommend that you get around 45–65% of your daily calories from carbs if you have diabetes.
However, a growing number of experts believe that people with diabetes should eat far fewer carbs. Many recommend less than half this amount.
Counting your carbs will help ensure that you stay within the range that’s best for you.
This article tells you how many carbs to consider eating if you have diabetes.
In this article
What are the different types of carbs?
There are three main types of carbs: sugars, starches, and fiber.
Sugar belongs to a category known as simple carbohydrates. Simple carbs have one sugar molecule (monosaccharides) or two sugar molecules (disaccharides).
Sugar is found naturally in foods and beverages like whole fruit, juice, milk products, and honey. It’s also added to processed foods such as candy.
Starches and fiber are both complex carbohydrates. Complex carbs have at least three sugar molecules. The body takes more time to digest, or break down, starches than sugar, and it can’t digest fiber at all.
Starches are found in foods like potatoes, corn, legumes, whole grain bread, and pasta.
Fiber is found in foods like fruits, vegetables, legumes, nuts, and whole grains. Unlike sugars and starches, naturally occurring fiber doesn’t raise your blood sugar level and may even slow its rise.
Many foods and beverages, such as rice, contain more than one type of carbohydrate.
Summary: The three main types of carbohydrates are sugars, starches, and fiber.
How does food affect blood sugar levels?
Many factors, including exercise, stress, and illness, affect your blood sugar levels. That said, one of the largest factors is what you eat.
Of the three macronutrients — carbs, protein, and fat — carbs have the greatest effect on blood sugar. That’s because your body breaks down carbs into sugar, which enters your bloodstream.
This occurs with all digestible carbs, including refined sources like chips and cookies as well as whole, unprocessed sources like fruits and vegetables.
When people with diabetes eat foods high in carbs, their blood sugar levels can surge. High carb intake typically requires high doses of insulin or diabetes medication to manage blood sugar.
Given that people with type 1 diabetes are unable to produce insulin, they need to inject insulin several times a day, regardless of what they eat. However, eating fewer carbs can significantly reduce their mealtime insulin dosage.
Summary: Your body breaks down certain carbs into sugar, which enters your bloodstream. People with diabetes who eat a lot of carbs require insulin or diabetes medication to keep their blood sugar from rising too much.
How many carbs should a person with diabetes have in a day?
Studies have shown that many different levels of carb intake may help manage blood sugar, and the optimal amount of carbs varies by individual.
The American Diabetes Association (ADA) used to recommend that people with diabetes get around 45% of their calories from carbs.
However, the ADA now promotes an individualized approach in which your ideal carb intake should take into account your dietary preferences and metabolic goals.
It’s important to eat the number of carbs at which you feel best and that you can realistically maintain in the long term.
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The typical American diet provides around 2,200 calories per day, with 50% of them coming from carbs. This is equivalent to 275 grams of carbs per day.
A severely restricted intake of fewer than 50 grams of carbs per day appears to produce the most dramatic results and may reduce or even eliminate the need for insulin or diabetes medication. This represents 9–10% of daily calories on a 2,000–2,200-calorie diet.
When tracking carb intake, experts sometimes recommend focusing on your net carbs instead of the total amount of carbs you eat. Net carbs are total grams of carbs minus grams of fiber.
People with diabetes can also benefit from diets that allow up to 26% of their daily calories to come from carbs. For people who eat 2,000–2,200 calories a day, this is equivalent to 130–143 grams of carbs.
Since carbs raise blood sugar, reducing them to any extent can help you manage your blood sugar levels. Therefore, figuring out how many carbs to eat requires some testing and evaluation to find out what works best for you.
For instance, if you’re currently consuming about 250 grams of carbs per day, reducing your intake to 150 grams should result in significantly lower blood sugar after meals.
Summary: There’s no one-size-fits-all recommendation for how many carbs people with diabetes should eat. However, having carbs account for no more than 26% of your daily calories may help you manage your condition.
How do you determine your optimal carb intake?
To determine your ideal carb intake, measure your blood sugar with a blood glucose meter before a meal and again 1–2 hours after eating.
To prevent damage to your blood vessels and nerves, the maximum level your blood sugar should reach is 180 milligrams per deciliter (mg/dL), or 10 millimoles per liter (mmol/L), 2 hours after eating. However, you may want to aim for an even lower ceiling.
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To achieve your blood sugar goals, you may need to restrict your carb intake to less than 10, 15, or 25 grams per meal. Also, you may find that your blood sugar rises more at certain times of the day, so your upper carb limit may be lower for dinner than for breakfast or lunch.
In general, the fewer carbs you consume, the less your blood sugar will rise and the less insulin or diabetes medication you’ll require to stay within a healthy range.
If you take insulin or diabetes medication, it’s very important to speak with a healthcare professional to ensure the appropriate dosage before reducing your carb intake.
Summary: Determining the optimal carb intake for diabetes management requires testing your blood sugar and making adjustments as needed based on your response, including how you feel.
Does carb restriction work for diabetes?
Many studies support the use of carb restriction in people with diabetes. Research has confirmed that many levels of carb restriction can effectively lower blood sugar levels.
Very low carb ketogenic diets
Very low carb diets typically induce mild to moderate ketosis, a state in which your body uses ketones and fat, rather than sugar, as its main energy sources.
Ketosis usually occurs at a daily intake of fewer than 50 grams of total carbs.
Very low-carb ketogenic diets were prescribed for people with diabetes even before insulin was discovered in 1921.
Several studies indicate that restricting carb intake to 20–50 grams per day can significantly reduce blood sugar levels, promote weight loss, and improve cardiovascular health for people with diabetes.
In addition, these improvements often occur very quickly.
For instance, in a small 3-month study, people consumed either a low-carb diet containing up to 50 grams of carbs per day or a calorie-restricted low-fat diet.
The low-carb group averaged a 0.6% decrease in hemoglobin A1c (HbA1c) and lost more than twice as much weight as the low-fat group. What’s more, 44% of them discontinued at least one diabetes medication compared with 11% of the low-fat group.
In several studies, participants have reduced or discontinued the use of insulin and other diabetes medications due to improvements in blood sugar control.
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Diets containing 20–50 grams of carbs per day have also been shown to lower blood sugar levels and reduce the risk of disease in people with prediabetes.
Although concerns have been raised that higher protein intake on low carb diets may lead to kidney problems, a 12-month study found that a very low carb intake didn’t increase the risk of kidney disease.
Another study found that the diet might improve kidney function in people with type 2 diabetes and normal renal function or mild kidney disease.
Low carb diets
Many low-carb diets restrict carbs to 50–100 grams, or about 10–20% of calories, per day.
Although there are very few studies on carb restriction in people with type 1 diabetes, those that exist have reported impressive results.
One of the biggest concerns for people with type 1 diabetes is hypoglycemia or blood sugar that drops to dangerously low levels.
In a small 12-month study from 2005, adults with type 1 diabetes who restricted their daily carb intake to fewer than 90 grams had 82% fewer episodes of low blood sugar than before they started the diet.
In a 2012 study on people with type 1 diabetes who restricted carbs to 70 grams per day, participants saw their HbA1c drop from 7.7% to 6.4%, on average. What’s more, their HbA1c levels remained the same 4 years later.
A 1.3% reduction in HbA1c is a significant change to maintain over several years, particularly in those with type 1 diabetes.
People with type 2 diabetes may also benefit from limiting their daily carb intake.
According to a research review, people who consumed no more than 26% of calories from carbs were 32% more likely to experience diabetes remission than people who mostly followed a low-fat diet. A person was considered in remission if their HbA1c was under 6.5%.
Moderate carb diets
A more moderate carb diet may provide 130–220 grams of carbs per day or 26–44% of calories in a 2,000-calorie diet.
A few studies examining such diets have reported good results in people with diabetes.
In a 2010 study of 259 people with type 2 diabetes, those who followed a Mediterranean diet providing 35% or fewer calories from carbs experienced a significant reduction in HbA1c. Over 12 months, HbA1c dropped 2.0% on average.
Summary: Studies demonstrate that restricting carbs may benefit people with diabetes. The lower your carb intake, the greater the effect on your blood sugar levels and other health markers.
What are some high-carb foods to avoid?
Many tasty, nutritious, low-carb foods raise blood sugar levels only minimally. You can enjoy these foods in moderate to liberal amounts on low-carb diets.
However, you should avoid or limit the following high-carb items:
- bread, muffins, rolls, and bagels
- pasta, rice, corn, and other grains
- potatoes, sweet potatoes, yams, and taro
- milk and sweetened yogurt
- most fruit, except berries
- cakes, cookies, pies, ice cream, and other sweets
- snack foods like pretzels, chips, and popcorn
- juice, soda, sweetened iced tea, and other sugar-sweetened drinks
- beer, wine, and spirits
Keep in mind that not all of these foods are unhealthy. For example, fruits are highly nutritious, but eating large amounts isn’t optimal for anyone trying to manage their blood sugar levels by eating fewer carbs.
Summary: On a low-carb diet, you should avoid or limit foods and beverages like beer, bread, potatoes, fruit, and sweets.
Are low-carb diets always best for diabetes?
Low carb diets have consistently been shown to lower blood sugar and improve other health markers in people with diabetes.
At the same time, certain higher-carb diets have been credited with similar effects.
For example, some studies suggest that low-fat vegan or vegetarian diets may lead to better blood sugar control and overall health.
In a 12-week Korean study, a brown-rice-based vegan diet containing 268.4 grams of carbs per day (about 72% of calories) lowered participants’ HbA1c levels more than a standard diabetes diet with 249.1 grams of total daily carbs (about 67% of calories).
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An analysis of four studies found that people with type 2 diabetes who followed a low-fat macrobiotic diet consisting of 70% carbs achieved significant reductions in blood sugar and other health markers.
The Mediterranean diet likewise improves blood sugar control and provides other health benefits in individuals with diabetes.
However, it’s important to note that most of these diets weren’t directly compared with low-carb diets, but rather with standard low-fat diets often used for diabetes management. More research on these diets is needed.
Summary: Studies suggest that certain higher carb diets may aid diabetes management. Still, additional research is needed.
If you have diabetes, reducing your carb intake may be beneficial.
Multiple studies have shown that a daily carb intake of up to 44% of calories not only leads to better blood sugar control but also may promote weight loss and other health improvements.
Here’s a sample menu, which would provide about 113 grams of total carbs for the day:
- Breakfast: 1 slice of whole wheat toast (about 14 grams of carbs) plus an omelet made with 2 large eggs (about 1 gram) and 1 cup of nonstarchy vegetables like broccoli and greens (about 10 grams)
- Lunch: 12 ounces of lentil soup (about 33 grams) and 1 apple (about 15 grams)
- Dinner: 4 ounces of grilled chicken breast (0 grams), 1.5 cups of nonstarchy vegetables like zucchini and okra (about 15 grams), and 4 ounces of brown rice (about 25 grams)
However, some individuals can tolerate more carbs than others.
Testing your blood sugar and paying attention to how you feel at different carb intakes can help you find your ideal range for optimal diabetes management, energy levels, and quality of life.