In a recent review published in the journal Dr Diabetes therapy, researchers weighed the evidence regarding ketogenic diets and their effectiveness in treating type 1 diabetes (T1D), type 2 diabetes (T2D), and gestational diabetes (GD). Their findings indicate that many questions remain unresolved and that much more investigation is needed before ketogenic diets can be included in clinical practice guidelines for diabetes.
Study: Does the ketogenic diet have a place in diabetes clinical practice? Review of current evidence and controversiess Image Credit: Chinnapong/Shutterstock
A growing global burden of diabetes
Diabetes, which results from conditions associated with compromised glucose-regulation and hyperglycemia, is a prevalent chronic disease worldwide. An estimated 108 million people were living with diabetes in 1980; That number has grown to more than 462 million today.
Different forms of diabetes have individual treatment protocols. For T2D, doctors may aim for drug-free remission or encourage management of a person’s glycated hemoglobin (HbA1c) to less than 7% or 53mml/mol. This can be achieved through lifestyle changes, such as increased activity and dietary changes, to maintain a goal weight. For T1D, the condition is metabolically irreversible and must be treated medically with insulin; However, diet can complement treatment.
Dietary modification for diabetes treatment
A fundamental component of diabetes management is weight loss of 15 kg, which is associated with improved glycemic control. Notably, there is still some uncertainty regarding dietary recommendations for people with diabetes who are already at a healthy weight.
For both T1D and T2D, the guidelines recommend a diet rich in whole grains, fruits, vegetables, nuts, legumes, and fish, and reducing artificial sweeteners, processed meats, and refined carbohydrates. Diabetic people are often told to consume high fiber and limit their saturated fat intake.
Generally, lifestyle interventions lead to a small temporary reduction in body weight, which is not sufficient to induce diabetes remission. This has led to interest in ketogenic or low-carbohydrate diets as a supplement to insulin-like treatments. These diets are characterized by high fat intake and moderate protein intake. However, conflicting evidence and lack of long-term data have prevented ketogenic diets from being included in diabetes management guidelines.
In the current review, researchers conducted a literature search through major medical databases such as Medline, Scopus, and PubMed, using the search terms ‘ketogenic,’ ‘low carbohydrate,’ and ‘very low carbohydrate.’
Evidence for the efficacy of low-carbohydrate and ketogenic diets
The ketogenic diet aims to achieve a blood ketone level of 0.5 to 3 mg/dL. These can be of different types depending on how restricted carbohydrate intake is. Some diets use grams to measure daily consumption of carbohydrates, while others use the percentage of daily energy from carbohydrates.
High-carbohydrate foods, such as potatoes, grains, rice, and bread, are often replaced with fatty animal proteins. However, consuming too much protein can reduce the effectiveness of the diet. Carbohydrate levels derived are based on the assumption that adults consume 2000 kcal per day, which may not be accurate. These inconsistencies make it difficult to generalize the results of different studies.
The ketogenic diet has been credited with rapid weight loss, but the physiological mechanisms are unknown. This may be due to reduced appetite and greater satiety when following a ketogenic diet. Scientists have not resolved whether these foods are beneficial in relation to insulin sensitivity and glycemia.
Short-term studies of 15 to 32 weeks showed that diabetic people who followed a low-carbohydrate diet had significant improvements in HbA1c and increased weight loss, and many reduced their anti-diabetic medication. Another study found that people with T2D reduced or stopped using insulin after following a low-carbohydrate diet for more than a year. There is also some indication that the ketogenic diet can improve blood pressure, preserve muscle mass, reduce fat and inflammation in people with diabetes, and improve overall quality of life.
Unanswered questions and need for further research
There are no long-term studies on whether the benefits of the ketogenic diet are sustained. Furthermore, there is doubt as to whether these benefits are primarily driven by weight loss and whether they can be achieved through another effective diet plan, such as a hypocaloric, very low-carbohydrate diet. There has been limited research on whether a ketogenic diet can benefit people with T2D with a healthy body mass index (BMI).
The ketogenic diet can also have certain side effects. They are high in saturated fat and processed meats, which can increase the risk of heart disease. Additionally, a high-protein diet can reduce kidney health. They can cause changes in calcium and bone metabolism in children and adults, increasing the risk of fractures in some populations.
Whether the ketogenic diet is appropriate for pregnant women with gestational diabetes has not been evaluated. Since they are high in animal protein, they need to be modified to be relevant for those following vegetarian and vegan diets. It can be helpful to focus on the quality of carbohydrates eaten, rather than cutting them out entirely.
The researchers also noted that adherence and high dropout rates are a challenge for many adherents of low-carbohydrate diets. To promote adherence and achieve safe and optimal results, the ketogenic diet should be carefully monitored and adjusted as needed. However, the lack of a universally accepted definition for the ketogenic diet is a barrier to research and implementation of the ketogenic diet for diabetes management.