Fact-checked by Dr. Anthony Gustin, DC, MS.
Written by Lorenz Mac
The ketogenic diet may be a way to control your blood sugar and help you lose weight. Both of these are critical to managing and preventing Type 2 diabetes.
Diabetes is one of the most common metabolic diseases in the country. And it’s on the rise. In 2015, 30.3 million Americans (9.4% of the population) had diabetes, and 1.5 million Americans are diagnosed with diabetes every year[*]. And that’s not counting the millions with prediabetes or those that go undiagnosed.
Most doctors agree that you can prevent Type 2 diabetes with special diets and lifestyle changes. But not everyone agrees on the right diet to do the job.
Luckily, there’s an overwhelming amount of research suggesting that a low-carbohydrate, high-fat ketogenic diet may help regulate blood sugar and get your diabetes symptoms back on track. Some experts claim the keto diet can reverse Type 2 diabetes completely.
In this article, you’ll learn diabetes and blood sugar basics, including:
- What Is the Keto Diet?
- What Is Diabetes?
- The Ketogenic Diet and Type 2 Diabetes
- How Does Fat Help Prevent Diabetes?
- Is Keto Safe for All Diabetics?
The ketogenic diet is a very low-carbohydrate, high-fat diet that takes your body from burning carbohydrates (glucose) for energy to using fat as fuel.
The diet was created for therapeutic purposes. It was designed in 1924 as a dietary therapy for childhood epilepsy, and now researchers are focusing their sights on the ketogenic diet and diabetes.
It makes sense. The keto diet is known for lowering blood sugar and making your cells more sensitive to insulin, so you won’t experience the crazy blood sugar highs and lows that come with eating a ton of carbs.
The ketogenic diet is also known for benefits like:
- Fat loss
- Better body composition
- More energy
- Better brain function
- Lower inflammation
But what if the keto diet could do more than just help you lose weight and think more clearly? What if keto could help people with diabetes become less insulin resistant and get their blood sugar back on track for good?
Let’s find out more about diabetes and how most people can reverse this common disease.
Before diving into the role of the ketogenic diet in diabetes, it’s important to understand how diabetes works and review some basic medical terms.
Diabetes is a disease that can occur when you have high blood sugar over a prolonged period of time, aka chronic high blood sugar[*].
Blood sugar (or blood glucose) is the result of your body breaking down the food you eat (mostly carbohydrates) into glucose. Your blood then delivers glucose via your bloodstream to all the cells in your body, where it’s used for energy.
Glucose is the main source of energy for most people — unless you’re in ketosis. We’ll get to that in a minute.
Insulin is a hormone produced by your pancreas to help transport glucose into your cells for energy. It looks like this:
- When you eat, your body breaks carbs down into glucose
- Glucose enters your bloodstream
- Your body senses a rise in blood sugar and your pancreas gets the memo to produce insulin
- Insulin helps transport glucose into your cells for energy
When your body doesn’t make enough insulin or doesn’t use it properly, sugar (glucose) stays in your bloodstream instead of getting delivered to your cells for energy.
Over time, excessive levels of circulating glucose results in a number of metabolic and inflammatory issues, aka diabetes.
The Two Main Types of Diabetes
Type 1 Diabetes
Type 1 diabetes is an organ-specific autoimmune disease that causes your immune system to destroy the cells in your pancreas responsible for producing insulin.
This happens due to a combination of genetic and environmental factors. As a result, people with Type 1 diabetes can’t produce insulin naturally and have to take insulin every day.
Despite sometimes being referred to as juvenile diabetes, you can develop Type 1 diabetes at any age. Type 1 accounts for just 5% of all diabetes cases in the United States[*].
Type 2 Diabetes
Type 2 diabetes is the most common form of diabetes, accounting for 95% of all diabetes cases in the United States[*].
In the case of Type 2 diabetes, you either become insulin resistant — meaning your pancreas is producing insulin, but your cells reject it. Or, your pancreas stops creating enough insulin to deal with chronically high blood sugar.
Either way, Type 2 diabetes is usually the result of chronically high blood sugar from poor diet and lifestyle choices.
You can develop Type 2 diabetes at any age, but it’s most common in middle-aged and older adults[*].
The ketogenic diet can help lower your blood glucose levels, which may help if you suffer from Type 2 diabetes. Using the ketogenic diet with other types of diabetes — like Type 1 or gestational diabetes — gets more complicated. More on that below.
With Type 2 diabetes, your body doesn’t respond to insulin correctly — also known as insulin resistance. When you’re insulin resistant, your cells can’t use your blood glucose for energy. Instead, the sugar builds up in your bloodstream, aka chronic high blood sugar.
Since a ketogenic diet switches your system from using glucose to creating and using ketones from fat as fuel, your blood sugar will naturally start to lower as you get into ketosis.
That’s why people who decide to follow a strict ketogenic diet start to see positive changes to blood sugar and insulin levels. Some people even claim that the keto diet can reverse or prevent Type 2 diabetes altogether.
Getting into ketosis involves a strict macronutrient ratio that you may not be used to. The most important part is that you’ll have to remove most starchy carbs from your menu.
Most people on keto restrict carbs to 30 grams or fewer per day. With such low carbohydrate intake, your body will naturally have lower blood sugar levels and require less insulin to move that sugar into your cells.
On top of that, the ketogenic diet can help you lose weight, which is crucial for diabetes prevention and management.
To recap, the keto diet can help:
- Improve insulin sensitivity[*]
- Decrease your blood sugar
- Help you lose unwanted fat[*]
- Gives you more energy[*]
- Reduces inflammation[*]
All of which help tremendously with diabetes management.
Can the Ketogenic Diet Cause Diabetes?
There is some confusion as to whether the ketogenic diet causes diabetes. This is because people mix up the terms ketosis and ketoacidosis. These are two completely different biological states, one of which provides a laundry list of benefits, while the other can be fatal.
When you change your main source of energy from glucose to fat, you increase your blood ketone level. More ketones in your blood is great news because your body and brain use ketones for quick, clean energy. When your blood ketone level is around 0.1 mmol/liter to 1.5 mmol/liter, you’re in nutritional ketosis.
Ketoacidosis, on the other hand, is referring to diabetic ketoacidosis, usually a complication of Type 1 diabetes. This happens when there is a dangerously high number of ketones in your blood — usually above 3.0 mmol/liter.
If you suffer from Type 1 diabetes or suspect that your ketone levels are too high, you can test your ketone levels with a blood ketone monitor or a breathalyzer.
The American Diabetes Association (ADA) recommends testing your ketone levels if your blood sugar is any higher than 240 mg/dL.
Aside from the confusion in terminology, there are no negative consequences to adopting a low-carb, high-fat diet for Type 2 diabetics when done correctly.
How to Enter Ketosis Naturally
Disclaimer: It’s important to consult with your primary physician before starting a ketogenic diet, especially if you are on any medication.
Getting into nutritional ketosis isn’t complicated, but it can be tough to get through the first couple of weeks.
To get into ketosis, you have to restrict your total carbohydrate intake and replace those carbs with healthy fats and a moderate amount of protein.
After a while, you will deplete your glycogen stores (store glucose in your muscles and other organs). Once you’re out of glucose and you continue to restrict carbs, your body will begin to make ketones from fat and use those ketones as energy.
This transition period when your body is switching from using glucose to burning fat is called keto-adaptation. And it can be rough. Stick it out if you really want to see the benefits of becoming fat adapted.
The longer you stick to keto, the more efficient your body will be at metabolizing fats as its main source of fuel.
Common Keto Macronutrient Ratios
The common macronutrient ratio for a standard ketogenic diet requires eating 70–80% of your calories from healthy fats, 5–10% from carbs, and 20–25% from protein.
Some diabetics steer away from keto due to the assumption that cutting carbs (like fruit) prevents you from getting the essential nutrients you need to stay healthy, but that’s not the case.
A healthy keto eating plan incorporates plenty of nutrient-dense, keto-friendly vegetables like kale, spinach, and collard greens. These vegetables contain hefty amounts of essential micronutrients like magnesium, vitamin A, and vitamin C. And healthy fats will help you to absorb these critical nutrients[*].
Monitoring Diabetes on a Ketogenic Diet
If you currently have diabetes and you want to try a ketogenic diet, you’ll want to involve your doctor or another qualified practitioner.
Monitoring your blood glucose and ketone levels is critical, especially as you’re transitioning into ketosis.
Some experts even recommend formal medical supervision in the beginning. As always, please talk to your doctor before you throw out all your carbs and dig into a jar of nut butter.
Once your body is acclimated to using ketones as energy, you should still make it a priority to regularly visit a physician to make sure the ketogenic diet is working properly for your body.
And because it’s likely that your diabetic symptoms will start to improve, you may need to alter your medication. Again, keep up with blood glucose and ketone monitoring and always ask your doc for the best advice.
Keto’s Promising Effects on Blood Glucose Levels
Dietary ketosis works for so many diabetics because it naturally lowers blood sugar and increases insulin sensitivity.
One convincing study from 2016 found that a low carb diet improved blood glucose levels and helped with weight loss in adults suffering from Type 2 diabetes[*].
By the end of the 10-week, low-carb study, nearly 60% of the 262 Type 2 diabetics reduced their diabetes medication or stopped taking it altogether.
Each subject was required to consume no more than 30 grams of carbs per day while increasing fats and proteins. In other words, they followed a ketogenic diet (it just wasn’t called that). Several smaller studies show similarly positive results.
Following a ketogenic diet has been shown to offer both long- and short-term benefits to those with diabetes.
The Diabetes Prevention Program conducted a study that followed 1,079 people with prediabetes. The results showed that 58% were able to prevent the progression of diabetes simply through losing weight and changing their diet[*].
Increasing your fat intake helps regulate hormones — including your hunger hormone, ghrelin — thereby mitigating any major food cravings. No major carb or sugar cravings? You’re much more likely to stick to a low-carb diet and keep those blood sugar levels low.
Another study performed by researchers at the Duke University Medical Center looked at 28 overweight people with Type 2 diabetes. During the four-month trial, they consumed a low-carb, high-fat ketogenic diet while simultaneously tapering off diabetes medications.
Researchers concluded that there was a 16% decrease in Hemoglobin A1c (HbA1c), a blood marker that measures your blood sugar over 2-3 months.
Participants also lost an average of 19 pounds, their triglyceride levels decreased by 41%, blood pressure levels improved, and their blood sugar levels decreased by 16%[*].
So clearly, eating more fat doesn’t make you fat! In fact, it can have quite the opposite effect and help you lose weight and regulate hormones when you also cut carbs.
Isn’t Saturated Fat Bad for You?
Many people are hesitant to follow the ketogenic diet because of its relatively high saturated fat content — and we all know how much saturated fat has been villainized over the past few decades.
Because of these antiquated guidelines, most doctors tell diabetic patients to keep their saturated fat intake to around 10% of their total calories[*].
Luckily, there is research suggesting that more saturated fat as part of a low-carb diet is beneficial for overall health, particularly if you have risk factors for diabetes and want to lose weight.
Low-Carb, High-Fat Diets for Health
One study in particular looked at 83 adults with a BMI of 33 (technically obese) and a high risk for Type 2 diabetes. They proceeded to divide them into three different diet groups with the same caloric intake[*]:
- One diet was a very low-fat diet, consisting of 20% protein, 70% carb, and 10% fat.
- The second diet was a high unsaturated fat diet containing 50% carb, 30% fat, and 20% protein.
- The third diet was a very low-carbohydrate diet with 20% protein, 61% fat, and only 4% carb.
For each diet, 20% of the total fats were saturated, and the subjects were placed on an exercise regimen.
At the end of the three-month study, there was an almost identical amount of body fat loss between the three diets. But the big surprise was that, compared to the other groups, the very low-carbohydrate diet group had improved markers of HDL or “good” cholesterol.
Insulin levels were also down by 34% in the very low-carb group, decreased by 18% in the high unsaturated fat group, and actually increased by 15% in the very low-fat group[*].
This shows that low-carb, high-fat ketogenic diets provide identical weight loss properties while simultaneously lowering overall insulin levels compared to other diets. Saturated fats shouldn’t be of concern if you have diabetes or are pre-diabetic as long as you are consuming them as part of a proper ketogenic diet.
With the overwhelming evidence supporting the ketogenic diet as a way to prevent diabetes, there are some precautions to consider.
If you have kidney disease, for instance, you need to regulate the amount of protein you eat. Too much or too little can cause complications.
The keto diet is traditionally a low- to moderate-protein diet, but some experts claim that you don’t need to limit protein intake to stay in ketosis. In any case, talk to your doctor about your optimal protein intake if you have kidney disease.
What about other forms of diabetes? Is ketosis still safe? Or even beneficial?
Is Keto Safe for Women With Gestational Diabetes?
Gestational diabetes (GD) manifests in pregnant women around the 24th-28th week of pregnancy. It causes high blood sugar levels and insulin resistance, which is dangerous for mom and baby.
Developing GD doesn’t mean you had diabetes before you got pregnant or that you’ll have it after. But it does raise your odds of getting Type 2 diabetes down the line.
There’s some debate on the best diet for women with GD.
The general “safe” consensus among mainstream health experts is that you should not follow a ketogenic diet while pregnant.
But the truth is, being in ketosis is a natural part of being human (it always has been) and while there aren’t many studies on GD and the ketogenic diet, if you dig around, you’ll find several positive anecdotal accounts.
So the answer isn’t so straightforward. Adopting a ketogenic diet might help mitigate symptoms of gestational diabetes, but it should be done with extreme caution and medical supervision.
Eating a low carbohydrate diet may be a better approach to help prevent and manage gestational diabetes. Just be sure to consult with your obstetrician before making any dietary changes so they can help guide you through the process.
Is Keto Safe for Type 1 Diabetics?
The short answer is maybe. The long answer is a little more complicated.
Type 1 diabetes isn’t just an autoimmune condition; it stops your pancreas from producing insulin at all.
This is different than Type 2, which causes a reduction in insulin production, or insulin resistance.
So, ketosis may not work with Type 1 diabetes for a couple of reasons:
- It doesn’t matter how low your blood sugar is; your pancreas will never produce insulin if you have Type 1 diabetes
- You’re more prone to low blood sugar when you have Type 1 diabetes
- You’re more prone to diabetic ketoacidosis when you have Type 1 diabetes — a dangerous condition that raises blood pH and could kill you[*]
However, some doctors, like Richard Bernstein, MD, who manages his own Type 1 diabetes with a very low carb approach, believe that ketogenic diets can help prevent blood sugar levels from spiking[*].
Halle Berry is another vocal proponent of the keto diet to help control her Type 1 diabetes and maintain a healthy weight[*].
Unfortunately, there aren’t any notable studies that prove the efficacy of the ketogenic diet with Type 1 diabetes. Definitely speak with your physician before altering your diabetes care plan.
How the Ketogenic Diet May Help Your Diabetes
The ketogenic diet may be a beneficial long-term diet for diabetes prevention and management.
Specifically, keto can help people with or at risk for Type 2 diabetes by:
- Promoting healthy weight loss
- Improving insulin sensitivity
- Regulating your hunger hormones to reduce food cravings
- Increasing levels of good cholesterol
- Improving HbA1c markers — your average blood sugar over 2-3 months
But it’s important to remember that no diet is one-size-fits-all.
The ketogenic diet could be great for those with Type 2 diabetes, but consider with caution if you have Type 1 or gestational diabetes, and only after consulting your doctor.
In fact, always consult with your doctor before starting a drastically new diet, especially if you’re currently taking medication.
And if you do give keto a spin? Monitor your blood glucose and ketone levels closely and make sure that low-carb, high-fat is right for your body.