The Ketogenic Diet and Diabetes

The ketogenic diet was originally developed almost 100 years ago to treat epilepsy. Nowadays, it is used as a nutrition plan by health-conscious men and women to optimize body composition and athletic performance.

Recent research suggests that high fat, very-low carb diets have another benefit: They may help control glucose, triglycerides, insulin, and body weight in people with diabetes. The research below shows the ketogenic diet may be an effective tool you can use to manage symptoms of Diabetes, alongside exercise and medication.

Before we get to research, we need to review some basic medical terminology. Diabetes is a group of metabolic diseases in which the body has elevated blood levels its main energy source: a sugar called glucose.

There are two reasons why this occurs. In some people, there is insufficient production of a chemical called insulin, a hormone produced by the pancreas that lower levels of glucose in the blood. People who suffer from low insulin levels have type I diabetes and they comprise approximately 5 to 10% of all diabetics. [1]

Type I diabetes is usually inherited and type I diabetics usually have to inject insulin to maintain proper levels of blood glucose. The other 90% to 95% of people with diabetes are type II diabetics. [1] In this version, the body doesn’t produce enough insulin for proper function or cells in the body do not react to insulin and take in sugar from the blood.

Type 2 diabetes is not inherited. However, lifestyle factors such as high body weight, poor exercise and eating habits all increase the risk of developing type 2 diabetes. [2] It can be managed by improving dietary and lifestyle habits and also using proper medication. [2]

Diabetes results in a higher concentration of serum blood glucose. Over time, this higher level of serum blood glucose leads to increased production of insulin, elevated levels of the energy-storing fat molecules called triglycerides, and generally increased body weight.

Because of excess sugar, red blood cells called hemoglobin are coated with sugar. These “sugar-coated” hemoglobin cells are called hemoglobin A1C- also known as HbA1c. Doctors will often measure the proportion of HbA1c to regular hemoglobin to determine if you have diabetes.

If not managed correctly, high blood sugar in diabetics can damage blood vessels and lead to a variety of illnesses. Unmanaged diabetes doubles the risk of cardiovascular diseases such as coronary artery diseases and stroke. [3, 4] Diabetes can damage small vessels in the eyes, kidneys, and nerves and lead to complications such as blindness and kidney disease. [4]

Diabetes is one of the most common chronic diseases in the world. In 2014, diabetes affected about 387 million people worldwide and resulted in $612 billion dollars of health-related costs. [5] Unfortunately, as a conventional western lifestyle of poor nutrition and exercise habits becomes more popular, diabetes is expected to affect about 592 million people worldwide. [6] In the United States alone, diabetes increased from 5.58 diagnosed cases in 1980 to 22.3 million diagnose cases in 2013. [7]


With the increasing prevalence, cost-burden, and long-term implications of diabetes, researchers are looking for a more effective method to prevent and manage symptoms of diabetes. Because ketogenic diets greatly restrict carbohydrate, some surmise that the ketogenic diet could be an effective dietary intervention. But is it effective and safe?

The Ketogenic Connection: Can Fat Fight Diabetes?

One of the first studies investigating the impact of a low-carbohydrate, ketogenic diet (LCKD) was performed by researchers at Duke University Medical Center in 2005. In their study, researchers recruited 28 overweight participants with type 2 diabetes for a 16-week intervention trial.

The subjects had a mean BMI of 42.2, mean age of 56 years, and were of either African-American or Caucasian descent. In their intervention, subjects consumed a LCKD diet with the goal of eating less than 20 grams of carbohydrates per day while reducing dosages of diabetes medication. Subjects also received nutritional counseling and medication adjustment every two weeks.

In the 21 subjects the successfully completed the study, scientists observed a 16% decrease in Hemoglobin Ac from baseline to week 16. [8] Subjects experienced an average decrease in body weight of 8.7 kg (19.2 lbs.). [8] Additionally, their average blood glucose levels decreased a total of 16.6% and their average triglyceride levels decreased 41.6%. [8]

Overall, most subjects reduced or discontinued their diabetes medications. The researchers concluded that “the LCKD can be very effective at lowering blood glucose.” [8] However, in order for the most effective outcomes, patients on LCKD should consult their doctor or someone capable of adjusting their medication. [8]


Key Takeaways: Adhering to a very low carbohydrate ketogenic diet (LCKD) can reduce key markers related to type II diabetes in overweight, male subjects such as BMI, body weight, and blood levels of glucose, triglycerides, and hemoglobin A1C.

Recommendations: If you are overweight and have type II diabetes, using a ketogenic diet could be a solution to manage symptoms and reduce medication use.

Ketogenic vs. Low-Calorie Diet for Type II Diabetes

In a 24-week long intervention study, researchers recruited 84 obese subjects with type 2 diabetes and randomly divided them into two groups. The first group of 42 received a low-glycemic diet with a 500 calorie/day deficit. The second group ate a very low carbohydrate ketogenic diet with less than 20 grams of carbohydrates per day without calorie restriction.

Both groups were also underwent identical exercise regimens and had same access to nutritional coaching and group meetings. Researchers measured key diabetes markers including fasting glucose, body mass index (BMI), body weight (kg) and hemoglobin A1c at the beginning of the study, the midpoint (week 12), and the end (week 24).

Both groups experienced no notable adverse effects in their health. In the 29 subjects who successfully completed the calorie-restricted diet, researchers observed an average 16% reduction in fasting glucose, 2.7 reduction in BMI, and loss of 6.9 kg of bodyweight. [9] However, in the 21 subjects that successfully completed the very-low carbohydrate ketogenic diet, subjects experienced an average 19.9% reduction in fasting glucose, 3.9 decrease in BMI, and loss of 11.1 kg of bodyweight. [9]

When compared to the calorie-restrict diet, the subjects who underwent the ketogenic diet experienced a reduction three times greater in hemoglobin A1C (1.5% vs. 0.5%). [9] In addition to observing greater improvements in diabetes-related markers, researchers observed a greater reduction in medication usage in subjects that underwent the ketogenic diet treatment. Thus, due to their overall findings, the researchers stated that “Lifestyle modification using low carbohydrate interventions is effective for improving and reversing type 2 diabetes.” [9]

ChangesindiabetesmarkersAnother study sought to broaden the scope of the ketogenic diet’s impact on weight and symptoms of diabetes by examining a large, non-white patient population. In 2012, researchers in the United Arab Emirates recruited 363 overweight and obese participants for a 24 week intervention trial.

102 of these subjects had type 2 diabetes. The subjects were divided into two groups: one consumed a low-calorie diet (LCD) while the other consumed a low-carbohydrate ketogenic diet (LCKD). Both also underwent equal exercise and nutritional training. Every four weeks, the researchers measured levels of waist circumference, blood glucose level, levels of glycosylated hemoglobin, and triglycerides.

At the conclusion of the intervention, both groups had improved in all metrics but “these changes were more significant in subjects who were on the LCKD as compared with those on the LCD.” [10]. As a result, the researchers supported the study outlined above and concluded that their “…study shows the beneficial effects of a ketogenic diet over the conventional LCD in obese diabetic subjects.” [10]

However, because the drop in glucose can be very sudden, it is very important to monitor blood glucose when using the ketogenic diet.

Key Takeaways: When compared to a calorie-restricted diet, a very-low carbohydrate ketogenic diet leads to greater improvements in symptoms associated with type II diabetes in obese subjects

Recommendations: If you are willing to undergo the strict ketogenic diet, it could be an effective method in managing symptoms associated with type II diabetes.

High-Fat Diets: Prevention for Diabetes?

Because ketogenic diets are usually high in saturated fats, many people suspect that they are unhealthy. The research shows that very-low carbohydrate diets are actually beneficial for overweight and obese people who suffer from type II diabetes. However, how do ketogenic diets affect the risk of type II diabetes in healthy subjects?

To investigate this further, researchers recruited 83 non-diabetic subjects with an average age of 48 and BMI of 33. They randomly divided them in one of three equal-calorie diets for 8 weeks. The first one, called the Very Low Fat diet (VLD) consisted of 70% carbohydrates, 10% fat, and 20% protein.

The second diet, called the high unsaturated fat diet (HUF) consisted of 50% carbohydrates, 30% fat, and 20% proteins. In this diet, the bulk of the fat calories (about 90%) were from unsaturated fats. The third diet, called the very low carbohydrate diets (VLCARB), consisted of 4% carbohydrates, 61% fat, and 20% proteins.

About 20% of the fats in this diet were saturated. All subjects also participated in a weight-loss exercise regimen and support from dieticians. Additionally, at the end of the eight weeks, all subjects underwent the same “weight-maintenance” diet and exercise regimen for four weeks.

At the end of this 12 week study, scientists observed similar loss in body fat and overall body weight in all three diets. However, they noted that the VLCARB ketogenic diet was “more effective in improving tracylglycerols, HDL cholesterol, fasting and post-meal glucose and insulin concentrations. More specifically, triacylglycerols decreased by 39.9% in VLCARB subjects, 4.0% in VLF subjects, and 9.6% in HUF subjects. [11]

Insulin levels decreased by 33.6% in VLCARB subjects, decreased by 18.7 % in HUF subjects, and actually increased by 15.1 % in VLD subjects. [11]


Key Takeaways: Ketogenic diets do not increase the risk of overweight subjects developing type II diabetes or other cardiovascular illnesses. In fact, they could help lower triglycerides and insulin levels when compared to other equal-calorie diets.

Recommendation: If your triglycerides, insulin, and post-meal glucose are high, consider using a ketogenic diet. However, make sure to monitor your cholesterol closely.

Low-Carb Diets and Type I Diabetes: Is there a Connection?

The bulk of studies examining the ketogenic diet focus on overweight or obese subjects with type II diabetes. But is the ketogenic diet an effective treatment for type I diabetics?

Unfortunately, there are no formal research studies examining the impact of the ketogenic diet on glycemic control in type I diabetics. However, a study from 2012 examined the effects of a reduced carbohydrate diet.

In it, researchers recruited 48 subjects with an average age of 24 years and had them consume a reduced carbohydrate diet (

For those that adhered to a reduced carbohydrate diet, their percentage of hemoglobin A1c (HbA1c) was 7.7%, 6.4%, and 6.4% at baseline, 3 months, and 4 years respectively. [12] This indicates that there was a lower serum glucose concentration in the blood.


Key Takeaways: No studies showing the effects of the ketogenic diet on symptoms of type I diabetics have been performed. However, one study suggests that a reduced carbohydrate diet could decrease the percentage of HbA1c in the blood.

Recommendations: If you are a type I diabetic, consider a ketogenic diet. Look at ketogenic recipes to get ideas on different meals that work for you.

Wrapping it up: Is the Ketogenic Diet right for you?

The ketogenic diet gets a lot of flak because it is a fairly extreme dietary regimen that challenges the conventional view of “high carbs, low fat”. However, an abundant amount of research supports that very-low carbohydrate, ketogenic diets are actually a healthy lifestyle choice for diabetes.

In fact, many studies suggest that ketogenic diets are more effective in managing and preventing diabetes when compared to low-calorie diets. In a recent critical evaluation of literature on carbohydrate restriction in managing diabetes, a group of 26 leading researchers stated that there is

“…evidence supporting the use of low-carbohydrate diets as the first approach to treating type 2 diabetes and as the most effective adjunct to pharmacology in type 1. They represent the best-documented, least controversial results.” [13]

Ketogenic diets are a valuable tool in managing symptoms of diabetes. Additionally, it is crucial to primarily eat healthful fats and a variety of foods.

At the end of the day, we only want to provide you with the evidence – and the ketogenic diet could very well be a healthy solution to manage diabetes. Consider talking to your doctor and dietitian to see if it’s a good fit for you.

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