Diabetes is a chronic disease that affects many people around the globe. Currently, more than 500 million people have diabetes worldwide (1).
Although diabetes is a complicated disease, maintaining good blood sugar levels can significantly reduce the risk of complications (2, 3).
One of the ways to achieve better blood sugar levels is to follow a very low carb diet, in which less than 10% of your total calories come from carbohydrates (4).
This article provides a detailed overview of very low carb diets for managing diabetes.
What is diabetes, and what role does food play?
Share on PinterestMapodile/Getty ImagesWith diabetes, the body can’t effectively process carbohydrates.
Usually, when you eat carbs, they’re broken down into small units of glucose, which are absorbed into the bloodstream.
When blood sugar rises, the pancreas responds by producing the hormone insulin. This hormone allows blood sugar to enter cells.
In people without diabetes, blood sugar levels remain within a narrow range throughout the day. For those who have diabetes, however, this system doesn’t work in the same way.
This is a big problem because having both too high and too low blood sugar levels can cause severe harm.
There are several types of diabetes, but the two most common ones are type 1 and type 2. Both of these conditions can occur at any age.
With type 1 diabetes, an autoimmune process destroys the insulin-producing beta cells in the pancreas. People with diabetes take insulin several times a day to ensure that glucose gets into the cells and stays at a healthy level in the bloodstream (5).
With type 2 diabetes, the beta cells at first produce enough insulin, but the body’s cells are resistant to its action, so blood sugar remains high. To compensate, the pancreas produces more insulin, attempting to bring blood sugar down.
Over time, the beta cells lose their ability to produce enough insulin (6).
Of the three macronutrients — protein, carbs, and fat — carbs have the most significant impact on blood sugar management. This is because the body breaks them down into glucose.
So, people with diabetes may need to take large doses of insulin, medication, or both when they eat a lot of carbohydrates.
Can very low carb diets help manage diabetes?
Many studies support very low carb diets for the treatment of diabetes (7, 8, 9, 10, 11, 12).
In fact, before the discovery of insulin in 1921, very low carb diets were considered standard treatment for people with diabetes (13).
Also, low carb diets seem to work well in the long term when people follow them consistently.
Many people find it challenging to adhere to a low carb diet long term because it is not a sustainable eating pattern. Several recent studies discuss this and how we need more studies to understand the long-term impacts of low carb diets (14, 15, 16, 17).
In one study, people with type 2 diabetes ate a low carb diet for 6 months. Their diabetes remained well managed more than 3 years later if they consistently followed the diet (18).
Similarly, when people with type 1 diabetes followed a carb-restricted diet, the 48% who followed the diet saw a significant improvement in blood sugar levels over a 4-year period (19).
What’s the optimal carb intake for people with diabetes?
The ideal carb intake for people living with diabetes is a controversial topic, even among those who support carb restriction.
A few older studies found significant improvements in blood sugar levels, body weight, and other markers when carbs were restricted to 20 grams per day (20, 21).
Dr. Richard K. Bernstein, who has type 1 diabetes, has eaten 30 grams of carbs daily and documented excellent blood sugar management in his patients who follow the same regimen (22).
However, other research shows that if a very low carb diet is too restrictive, a low carb diet, such as 70–90 grams of total carbs, or 20% of calories from carbs, is also effective (18, 23, 24).
The ideal amount of carbs may also vary by person because everyone has a unique response to carbs, and carb needs are determined by age, weight, height, sex, and activity level.
According to the American Diabetes Association (ADA), there’s no one-size-fits-all diet that works for everyone with diabetes. Personalized meal plans, which consider your dietary preferences and metabolic goals, are best (25).
The ADA also recommends that people work with their healthcare team to determine their proper carb intake.
To figure out your ideal amount of carbs, you may want to measure your blood glucose with a meter before a meal and again 1 to 2 hours after eating.
Per the ADA standards of care, the target blood sugar for 2 hours after a meal is below 180 mg/dL. Consistently high blood sugars (over 180 mg/dL) over a long period lead to complications like nerve or kidney damage (26).
It all depends on your tolerance and the macronutrient balance of your meals. Just remember that pairing carbs with protein and fat will slow glucose absorption, slowing blood sugar rise.
And, instead of eliminating all carbs, a healthy low carb diet should include nutrient-dense, high fiber carb sources, like vegetables, berries, nuts, and seeds.
Which carbs raise blood sugar levels?
In plant foods, carbs comprise a combination of starch, sugar, and fiber. Only the starch and sugar components raise blood sugar.
Fiber naturally found in foods, whether soluble or insoluble, does not break down into glucose in the body and doesn’t raise blood sugar levels.
You can subtract the fiber and sugar alcohols from the total carb content, leaving you with the digestible or “net” carb content. For example, 1 cup of cauliflower contains 5 grams of carbs, 3 of which are fiber. So, its net carb content is 2 grams (27).
Prebiotic fiber, such as inulin, has even been shown to improve fasting blood sugar and other health markers in people with type 2 diabetes (28).
Sugar alcohols, such as maltitol, xylitol, erythritol, and sorbitol, are often used to sweeten sugar-free candy and other “diet” products.
Some of them, especially maltitol, can raise blood sugar levels in people with diabetes (29).
For this reason, use the net carb tool cautiously — the count listed on a product’s label may not be accurate if all the carbs contributed by maltitol are subtracted from the total.
Furthermore, the Food and Drug Administration (FDA) or the ADA do not use the net carb tool. In fact, the ADA explicitly recommends not using net carbs to calculate carb intake for blood sugar management (30).
This carb counter may be a valuable resource. It provides data on total carbs, net carbs, fiber, protein, and fat for hundreds of foods.
Foods to eat and foods to limit
It’s best to focus on eating low carb, whole foods with plenty of nutrients.
It’s also essential to pay attention to your body’s hunger and fullness cues, regardless of what you’re eating.
Foods to eat
You can eat the following low carb foods until you’re full. Also make sure to get enough protein at each meal:
- meat, poultry, and seafood
- eggs
- cheese
- non-starchy vegetables (most vegetables except those listed below)
- avocados
- olives
- olive oil, coconut oil, butter, cream, sour cream, and cream cheese
Foods to eat in moderation
You can eat the following foods in smaller quantities at meals, depending on your personal carb tolerance:
- Berries: 1 cup or less
- Plain, Greek yogurt: 1 cup or less
- Cottage cheese: 1/2 cup or less
- Nuts and peanuts: 1–2 ounces, or 30–60 grams
- milk: 1 cup or less
- fruit other than berries, 1/2 cup or less
- Flaxseeds or chia seeds: 2 tablespoons
- Dark chocolate (at least 85% cocoa): 30 grams or less
- Winter squash (butternut, acorn, pumpkin, spaghetti, and hubbard): 1 cup or less
- Liquor: 1.5 ounces, or 45 mL
- Dry red or white wine: 4 ounces, or 120 mL
Legumes, such as peas, lentils, and beans, are healthy protein sources, though they also have carbs. Be sure to include them in your daily carb count.
Significantly reducing carbs usually lowers insulin levels, which causes the kidneys to release sodium and water (31).
Try to eat a cup of broth, a few olives, or some other salty, low carb foods to make up for the lost sodium. In this case, adding a little extra salt to your meals is appropriate. Still, limit daily sodium intake to no more than 2,300 milligrams (mg) for overall health (32).
However, if you have congestive heart failure, kidney disease, or high blood pressure, talk with your doctor before increasing the amount of sodium in your diet.
Foods to limit
These foods are high in carbohydrates and can significantly raise blood sugar levels in people with diabetes:
- white bread, pasta, refined cereal, corn, and other refined grains
- starchy vegetables, like potatoes, sweet potatoes, yams, and taro
- juice, soda, punch, sweetened tea, etc.
- beer
- desserts, baked goods, candy, ice cream, etc.
A sample day of very low carb meals for people with diabetes
Here’s a sample menu with 15 grams or less of digestible carbs per meal. If your personal carb tolerance is higher or lower, you can adjust the serving sizes.
Breakfast: Eggs and spinach
- 3 eggs cooked in butter (1.5 grams of carbs)
- 1 cup sautéed spinach (3 grams of carbs)
You can pair your eggs and spinach with:
- 1 cup blackberries (6 grams of carbs)
- 1 cup coffee with cream and optional sugar-free sweetener
Total digestible carbs: 10.5 grams
Lunch: Cobb salad
- 3 ounces (90 grams) cooked chicken
- 1 ounces (30 grams) Roquefort cheese (1/2 gram of carbs)
- 1 slice bacon
- 1/2 medium avocado (2 grams of carbs)
- 1 cup chopped tomatoes (5 grams of carbs)
- 1 cup shredded lettuce (1 gram of carbs)
- olive oil and vinegar
You can pair your salad with:
- 20 grams (2 small squares) 85% dark chocolate (4 grams of carbs)
- 1 glass of iced tea with optional sugar-free sweetener
Total digestible carbs: 12.5 grams.
Dinner: Salmon with veggies
- 4 ounces grilled salmon
- 1/2 cup sautéed zucchini (3 grams of carbs)
- 1 cup sautéed mushrooms (2 grams of carbs)
To complement your meal and for dessert:
- 4 ounces (120 g) red wine (3 grams of carbs)
- 1/2 cup sliced strawberries with 1 tbsp unsweetened whipped cream (5 grams of carbs)
- 1 ounce chopped walnuts (6 grams of carbs)
Total digestible carbs: 19 grams
Total digestible carbs for the day: 42 grams
For more ideas, here’s a list of seven quick low carb meals and a list of 101 healthy low carb recipes.
Talk with your doctor before changing your diet
When carbs are restricted, there’s often a significant reduction in blood sugar.
For this reason, your doctor will often reduce your insulin and other medication dosages. In some cases, they may eliminate your medication altogether.
One study reported that 17 of 21 study participants with type 2 diabetes were able to stop or reduce their diabetes medication when carbs were limited to 20 grams a day (33).
In another study, participants with type 1 diabetes ate 25-75 g of carbs daily for 12 weeks and saw improved blood sugar management and reduced insulin use. No changes in low blood sugar or adverse events were reported (9).
If insulin and other medications aren’t adjusted for a low carb diet, there’s a high risk of dangerously low blood glucose levels, also known as hypoglycemia.
So, it’s vital that people who take insulin or other diabetes medications speak with their doctor before starting a low carb diet.
Other ways to lower blood sugar levels
In addition to following a low carb diet, physical activity can also help manage diabetes by improving insulin sensitivity. A combination of resistance training and aerobic exercise is especially beneficial (34).
Quality sleep is also crucial. Research has consistently shown that people who do not get enough sleep have an increased risk for developing diabetes (35).
One recent observational study found that people with diabetes who slept fewer than 6 hours or more than 8 hours per night had worse blood glucose management than those who slept between 6 and 8 hours (36).
Another key to good blood sugar management is managing your stress. Yoga, qigong, and meditation have been shown to lower blood sugar and insulin levels (37).
The bottom line
Studies show that low carb diets can effectively manage type 1 and type 2 diabetes.
Low carb diets can improve blood sugar management, decrease medication needs, and reduce the risk of diabetic complications.
Remember to talk with your doctor before making dietary changes. Your medication dosages may need to be adjusted.
5 Foods to avoid (or limit) on a low carb diet
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