Can a Very-Low-Carb Diet Help People with Type 1 Diabetes?

Mention the words “carbohydrate” and “diabetes” in the same sentence and you’re likely to get a wide variety of reactions. Carbohydrate is wrought with controversy, and there clearly are differing opinions about whether carbs are the good guys, the bad guys, or maybe somewhere in between. Not surprisingly, many people who have diabetes find that cutting their carb intake improves their diabetes control. This enables them to more easily achieve A1C and blood sugar goals, and even helps to reduce the amount of diabetes medicine they need to take.

Why low carb?

Carbohydrate, or carb, is one of three main nutrients found in food. Protein and fat are the other two. Carb is digested into glucose, whereas protein is digested into amino acids and fat is broken down into fatty acids. Some of the glucose from carb digestion enters the bloodstream, raising blood glucose (sugar) levels. It’s pretty basic nutrition, and is a very good argument for those who support a low-carb diet for diabetes management.


Low-carb diets are nothing new, by the way. In fact, well before insulin was discovered in 1921, very-low-carb diets were pretty much the only way to treat diabetes. And more recent studies indicate that a low-carb diet seems to work well for both people with Type 1 and Type 2 diabetes — as long as folks adhere to it, of course. Many advocates of low-carb living claim that a low-carb diet is the best way to lower your A1C, thereby reducing the risk of diabetes-related complications. On the flip side, other research shows that low-carb diets may be effective in improving glycemic control and for weight loss, but those improvements aren’t sustained longer-term.

How low is low?

One of the tricky aspects of jumping on the low-carb bandwagon is to figure out what “low carb” and even “very low carb” actually mean. There’s no standard definition, so the term “low carb” is open to interpretation. (The Food and Drug Administration has not legally defined this term.) A study published in the journal Archives of Internal Medicine in 2006 defined a low-carb diet as being no more than 60 grams of carb per day. Another study in the British Journal of Nutrition in 2013 described low carb as being less than 40 grams of carb per day. To give you some perspective, the dietary reference intake for carbohydrate is set at 45 to 65 percent of total calories, and no less than 130 grams of carb per day. In general, men typically consume about 200 to 330 grams of carb daily and women, 180 to 230 grams of carb daily.

Dr. Richard Bernstein, an endocrinologist and person with Type 1 diabetes, advocates a low-carb, high-protein diet for his patients. No more than about 30 grams of carb per day is his advice. This is equivalent to eating two slices of bread or a small baked potato (both of which are discouraged on his diet, by the way). Phase 1 of the Atkins diet consists of no more than 20 grams of carb daily; you can also start off with the Atkins 40 program and boost your carb intake to 40 grams of carb daily.

Until there is a universally accepted definition of what low carb and very low carb means, a suggested guideline has been proposed by Richard Feinman from State University of New York Downstate Medical Center and his colleagues. This guideline is featured in the January 2015 of the journal Nutrition:

• Very low carbohydrate ketogenic diet: 20–50 grams carb per day or less than 10 percent of a 2000 calorie diet
• Low-carbohydrate diet: less than 130 grams of carb per day or less than 26 percent of calories from carb
• Moderate-carbohydrate diet: 26–45 percent of calories from carb
• High-carbohydrate diet: more than 45 percent of calories from carb

Now, about a low-carb diet for those with Type 1 diabetes…

Several weeks ago, a study was published in the journal Pediatrics, suggesting that people with Type 1 diabetes could follow a very-low-carbohydrate diet (VLCD) and achieve glycemic control. Interestingly, this study included both adults and children who had Type 1 diabetes.

In this study, subjects were recruited from a Facebook community for Type 1 diabetes called TypeOneGrit. Members of this group follow a VLCD (no more than 30 grams of carb per day) as outlined in the book Dr. Bernstein’s Diabetes Solution. Members of this group age 18 and older were recruited, and included parents of a child with Type 1 diabetes. Eligibility consisted of having Type 1 diabetes, taking insulin, and following a carb-restricted diet for at least three months. The number of subjects who were eligible and who provided sufficient information on an online survey amounted to 300. The findings?

• Mean (average) daily carb intake was 36 + 15 grams
• Mean reported A1C was 5.675 + 0.66 percent
• Mean daily insulin dose was 0.4 + 0.19 units/kilogram per day
• 97 percent achieved the American Diabetes Association glycemic targets
• Average blood glucose was 104 + 16 mg/dl
• A1C increased 0.1 percent per 10 grams of carb consumed

In addition, self-reported rates of adverse events were low: 205 participants reported having few (1–5) episodes of hypoglycemia per month, seven reported hypoglycemia with seizure or coma, and 11 required glucagon in the past year. The rate of hospitalizations for diabetic ketoacidosis was also low. Participants reported a high level of satisfaction with their health and their diabetes management, but not with their professional diabetes care (only 49 percent agreed that their health-care providers were supportive of their diet).

The results of the study are definitely intriguing and even promising. Yet, this study was an observational study, relying on self-reported data, and not a randomized trial with a control group, so what about the accuracy of the data? Here’s what Belinda Lennerz, MD, PhD, of Boston Children’s Hospital and one of the researchers had to say:

“While we did not specifically confirm dietary intake with medical records, I don’t have a reason to question the accuracy or truthfulness of the reported carbohydrate intake, given the otherwise high concordance of participant- and provider-reported information. The average carbohydrate intake of 36 grams a day is close to what is recommended in Dr. Bernstein’s Diabetes Solution (30 grams), a book that forms the basis for this online community.”

Others in the medical community have expressed some concern about the sustainability of a VLCD diet for people with Type 1 diabetes, as well as possible ramifications of such as stringent diet for children with the condition. Dr. Lennerz admits that “sustainability is the big question.” Some of the study participants had been on a VLCD for many years, and were doing well. When I asked her how realistic this diet would be for children, she replied, “The question of how well children will do directly relates to the family setting. If parents are able to provide a variety of tasty, low-carbohydrate choices and follow the approach as a family, I would expect that especially young children could do very well with this.”

Is a VLCD for you?

Eating less carbohydrate may be a step in the right direction if you’re dissatisfied with your level of glycemic control. Obviously, some people do well (in more ways than one) with cutting carbs; others — well, not so much. The researchers clearly acknowledge that the participants in this study may not be representative of all people with Type 1 diabetes, and they did not obtain detailed information about the subjects’ diet or diabetes management plan. More research is needed.

Limitations aside, this particular study certainly is evidence that some people have done well with averaging 36 grams of carb a day. If this seems appealing to you, bear in mind that your food intake will focus primarily on vegetables, nuts, meat, seafood, cheese, cream, and butter. What about fruit, bread, pasta, or rice? Well, not so much. And if a very-low-carb or even a low-carb diet doesn’t seem doable to you, there are other dietary approaches that you can try, such as the Mediterranean eating plan, for example.

Dr. Lennerz adds, “Individuals who would like to try a VLCD for diabetes self-management should keep in mind that this approach requires insulin dose adjustments and other adaptations in diabetes care, and should only be pursued under close supervision of a knowledgeable diabetes care provider.” Excellent advice for anyone considering a major overhaul to their diet or even to their lifestyle.

Want to learn more about low-carb diets and diabetes? Read “Carbohydrate Restriction: An Option for Diabetes Management” and “Low-Carb Diabetes: What You Need to Know,” then try our top seven low-carb recipes.

  • Kok-Hong Wong

    Perhaps the day will arrive when diabetes care providers are knowledgeable and supportive of VLCD for diabetes self-management. Based on the study “Participants reported a high level of satisfaction with their health and their diabetes management, but not with their professional diabetes care (only 49 percent agreed that their health-care providers were supportive of their diet).”