Low-Carb Diets Recommended for People with Diabetes — But How Low Is Low Enough?
Research continues to support the idea that reducing the amount of carbohydrates in your diet is a worthwhile goal for anyone with diabetes.
Through the combined effort of Bispebjerg Hospital, Aarhus University, and the University of Copenhagen, researchers recently reported that a reduced-carbohydrate diet helped with both blood sugar levels and triglycerides in people with type 2 diabetes.
The study consisted of 28 people with type 2 diabetes. They were monitored for a total of 12 weeks: six weeks eating a traditional high-carbohydrate diet and six weeks eating a lower-carbohydrate diet.
The lower-carbohydrate diet was also high in protein, moderate in fat, and included carbohydrates with a lower glycemic index.
Participants were asked to avoid weight loss to ensure that any improvements seen in blood sugar levels were a direct result of nutritional changes instead of potentially improved insulin sensitivity.
Dr. Thure Krarup, a senior hospital physician at Bispebjerg Hospital and a lead researcher on the study, says he’s pleased with the results because blood sugar levels and A1C improved, and the participants’ stored liver fat noticeably improved, too.
“Our study confirms the assumption that a diet with a reduced-carbohydrate content can improve patients’ ability to regulate their blood sugar levels — without the patients concurrently losing weight,” explained Krarup.
“Our findings are important because we’ve removed weight loss from the equation,” he added. “Previous studiesTrusted Source have provided contradictory conclusions, and weight loss has complicated interpretations in a number of these studies.”
Krarup says the next step is to create a larger and more controlled study to further illustrate the importance of carbohydrate reduction in the treatment of type 2 diabetes.
But his most recent research is vague on just how many grams of carbohydrates you should eat and what specific types were cut out or reduced during the study.
Research on low-carb diets
Other diabetes experts working directly with people on a daily basis recommend reading these types of studies with a grain of salt.
“What does the average person hear when they read the headline? That broccoli and apples are bad for you? Patients get so confused,” Jennifer Okemah, RD, CDE, author of a recent studyTrusted Source on the lack of clinical inertia in the treatment of people with type 2 diabetes, told Healthline.
While working one-on-one with clients, Okemah says people hear “low-carb” and immediately assume it means “no carb” and that all carbohydrates are bad for you.
That perspective sets them up for unsustainable restriction and inevitable failure.
Okemah emphasizes that these studies need to do a better job of defining what “low-carb” really means.
“Is it a low-carb diet? Or is it just lower? There’s a big difference between the two. And if it’s lower, lower than what?” she said.
The results of the recent study didn’t surprise her either.
“Of course you’re going to have a positive impact on your blood sugar, because you’re inevitably reducing the amount of garbage carbohydrates in your diet, which also has a huge impact on the amount of fat stored in your liver through improving your triglycerides — which are made up of both excess glucose and excess fat in your bloodstream,” Okemah said.
Non-alcoholic fatty liver disease (NAFLD) is a frequent comorbidity in people with type 2 diabetes. If ignored, it can easily lead to liver swelling, cancer, organ failure, and pancreatitis.
“The extra liver fat essentially ‘chokes out’ the liver. It’s kind of like when you go to a fancy restaurant and you order foie gras, which is duck liver that is super high in fat because those ducks were purposefully fattened and actually develop NAFLD. And we love how it tastes,” explained Okemah.
“Through diets high in heavily processed carbohydrates and sugary beverages, we are making ourselves the human version of foie gras,” she said.
Doing more harm than good?
Other recent research, published in Nature CommunicationsTrusted Source, reports conflicting results of a “high-fat” or “imbalanced” diet but lacks specifics on what that type of diet actually looks like.
The research was conducted through the Toronto General Hospital Research Institute and the department of pathology at University Health Network in Toronto.
In it, researchers said a fatty diet negatively affects your gut’s immune system and leads to the production of an antibody protein called IgA.
“IgA is naturally produced by our bodies and is crucial to regulating the bacteria that live in our gut,” said Helen Luck, a researcher at the Toronto institute and a lead study author.
“It acts as a defense mechanism that helps neutralize potentially dangerous bacteria that take advantage of changes to the environment, such as when we consume an imbalanced or fatty diet,” she said.
IgA B cells play a critical role in regulating the harmful bacteria that develop in your gut and inflammation overall.
Inflammation also plays a key role in the development of diabetes and overall insulin resistance. By improving IgA levels through changes in your diet, the research suggests it could be an effective approach to preventing, reversing, and treating type 2 diabetes.
“If we can boost these IgA B cells or their products, then we may be able to control the type of bacteria in the gut,” said Dr. Dan Winer, a scientist at the Toronto institute and a study co-author.
“Especially the ones that are more likely to be linked to inflammation and ultimately insulin resistance. Going forward, this work could form the basis for new gut immune biomarkers or therapies for obesity and its complications, like insulin resistance and type 2 diabetes,” he said.
Where does the keto diet fit in?
Strict low-carbohydrate diets were introduced to the diabetes community largely by Dr. Richard K. Bernstein, the author of “Dr. Bernstein’s Diabetes Solution.“
He’s advocated for severe low-carbohydrate diets — even excluding nonstarchy vegetables — as a critical part of treating diabetes. He was often dismissed by the medical community.
In recent years, the keto diet, which is similar to Bernstein’s diet, has gained popularity. It encourages a total carbohydrate consumption of 20 grams of net carbs (which means after dietary fiber has been subtracted) per day.
The effect is that the body begins burning more body fat for fuel. That results in ketones the entire body can use for fuel instead of glucose.
But Okemah cautions against committing too fully to a diet this strict in carbohydrate consumption.
“The human body will try to create glucose out of anything it can,” Okemah said. “It is the primary fuel source. And your central nervous system needs glucose. It will not run on ketones like many ketogenic diet books tell you.”
This is why people with type 1 diabetes will find that during a keto diet, they still need some insulin for meals high in protein and fat but void of carbohydrates. Albeit, the insulin amount is generally lower.
One client Okemah describes is a middle-aged man who has been following a ketogenic diet, seen his insulin needs drop significantly, but also struggles with brain fog, inability to focus, and overall lack of energy. He appreciates the benefits to his insulin needs and blood sugar management and accepts the changes in energy as part of the deal.
“Human physiology has not changed in 10,000 years,” Okemah said. “We keep trying to trick our physiology. Metabolically, yes, you can make some changes by depriving the body of an entire macronutrient like carbohydrates. But what’s the cost?”
“Many of my patients will see the ketogenic diet hype in the media and try it for a few weeks or a couple of months, and then say, ‘Ugh, that was painful,’ and then catapult back to previous poor behaviors around food, eating highly processed garbage carbs. It’s like a rubber band stretching, and then it springs back when you let it go,” she said.
Quality vs. quantity
Instead, Okemah says the focus should be on eating more quality carbohydrates and reducing highly processed carbohydrates, including sugary beverages.
“If I have a patient who wants to go on a ketogenic diet, I try to support them,” she explained, “but I also try to get them to modify it by including more green vegetables like broccoli or Brussels sprouts. You need prebiotics and probiotics from vegetables. Let’s not demonize an entire food group.”
With clients who stick to a ketogenic diet long term, Okemah sees a reduction in triglycerides, because of the drastic reduction in processed carbohydrates, and usually a significant rise in LDL (bad) cholesterol.
The American Diabetes Association has recently endorsed a low-carbohydrate diet consisting of approximately 40 percent of daily calories coming from carbohydrates — much higher than a ketogenic diet.
However, the organization emphasizes there’s no one-size-fits-all approach.
Okemah agrees, emphasizing that it comes down to the individual and creating a healthier diet they can ideally sustain long term, with more focus on the quality of the carbohydrates they’re eating rather than the quantity.
“I don’t want my patients to fear food,” she explained. “If it grows on Earth and it looks like what it did when it grew on the Earth, it’s probably OK for you.”