Is the Keto Diet Safe for People With Diabetes?

The ketogenic (keto) diet has become a popular trend among people trying to lose weight. Since the diet significantly restricts carbohydrates (carbs), it can change the way your body processes sugar and fat. 

If you have diabetes, you may be wondering if this diet is right for you. The answer to this question is more complex than it seems. The keto diet may not be the best long-term strategy to improve diabetes. 

Here, we’ll review the research and what it tells us about the positive and negative ways this particular diet can affect people with diabetes. 

What is the keto diet?

The keto diet is a diet low in carbohydrates that aims to put your body into a state of “ketosis.” Ketosis is a sort of “starvation mode.” And this triggers your body to burn fat — instead of sugar — for fuel. So, when your body is in ketosis, fat stores are used up and blood sugar levels remain low. 

People who follow a keto diet usually restrict themselves to a total of 50 g of carbs daily. To compare, the average well-balanced diet for someone with diabetes usually contains 200 g to 225 g of carbs. 

Does the keto diet help diabetes?

There’s growing evidence to suggest that the keto diet can be good for people with diabetes, especially those with Type 2 diabetes. Cutting back on carbs can lead to better blood sugar management. But the keto diet is hard to stick with, and it may not work for everyone. It also comes with some risks, and experts don’t know if it’s helpful in the long run.

Right now, there are no official guidelines that recommend the keto diet for diabetes. Let’s take a closer look at the possible pros and cons.

Benefits of a ketogenic diet for diabetes

Following a ketogenic diet may have benefits that are especially helpful for people with diabetes. 

Keto diet and blood sugar levels

People with diabetes have a harder time processing carbs, because their body doesn’t make insulin properly. This can lead to high blood sugar levels. 

EXPERT PICKS: WHAT TO READ NEXT

• Natural ways to lower blood sugar: Cutting back on carbs isn’t the only way to manage blood sugar. Learn about lifestyle changes that can help. 

• Best foods for diabetes: There are plenty of food options that are helpful for diabetes — without avoiding any food groups. Learn what foods to prioritize and what to limit. 

• Signs of ketosis: If you’re starting a keto diet for the first time, how can you tell if you’re in ketosis? Here are five signs to watch for.

Research suggests that a ketogenic diet improves blood sugar and hemoglobin A1C (HbA1C or A1C). Your A1C is a blood test that measures the average amount of sugar in your blood over the past 2 to 3 months. Some studies suggest that these changes can be seen after 3 weeks of starting a ketogenic diet. 

Keto diet and weight loss 

Following a ketogenic diet can lead to lower weight. This can be especially helpful for people with Type 2 diabetes. Weight loss can lower your risk of getting diabetes or prediabetes. Losing weight can also help people with diabetes respond better to insulin. 

For people with diabetes, following a keto diet seems to lead to more weight loss than a regular low-carb diet. But most of the research looks at short-term results (weeks to months). It’s not clear if a ketogenic diet supports lower weight long term. The studies on long-term weight loss are mixed. And there aren’t enough of them to know the diet’s impact long term. 

Keto diet and lowered insulin medication

People with diabetes who follow a ketogenic diet may be able to lower their insulin or other diabetes medications. That’s because eating fewer carbs can help reduce blood sugar spikes. So, the body may not need as much insulin to manage them. 

In some studies, people with Type 2 diabetes were able to reduce or even stop certain diabetes medications after starting a keto diet. But this should only be done under medical supervision. 

Why might the keto diet be bad for someone with diabetes?

While the keto diet may offer benefits for some people with diabetes, it also comes with potential downsides. These include both practical challenges and health risks — especially if the diet is followed without medical supervision.

Difficult to maintain

One of the biggest challenges of the ketogenic diet is sticking with it. The keto diet limits many common foods, including: 

• Bread

• Fruit

• Beans

• Starchy vegetables 

So, the diet can feel restrictive and hard to follow long term. Social situations, travel, or even just meal planning at home can become more complicated. 

Many studies have found that the ketogenic diet is hard to sustain, especially when using it as a long-term strategy. This limits how effective it can be. 

Nutrient deficiencies

Cutting out major food groups can make it harder to get all the nutrients your body needs. A strict keto diet can lead to low intake of important vitamins and minerals. One study found that the keto diet and Mediterranean diet were both helpful for managing diabetes. But the keto diet provided less of the following nutrients: 

• Fiber

• Thiamin

• Phosphorus

• Vitamins B6, C, D, and E

If you have diabetes, it’s likely safer and more sustainable to cut back on carbs gradually, rather than decreasing rapidly with the keto diet.

Risk of diabetic ketoacidosis

The ketogenic diet may increase the risk of a serious complication called diabetic ketoacidosis (DKA). This happens when the body produces too many ketones and they build up in the blood. This makes the blood acidic, and it leads to the buildup of dangerously high blood sugar levels. Unlike ketosis, which is expected on the keto diet, DKA is dangerous and can be life-threatening. The risk of DKA is higher in people with Type 1 diabetes. 

Experts disagree on whether it’s safe for someone with Type 1 diabetes to follow the keto diet because of the increased risk of DKA. If you have Type 1 diabetes and are thinking about trying the keto diet, talk to your healthcare team first. This diet should only be done with close medical supervision, regular monitoring, and a clear plan for managing your blood sugar and ketone levels.

Is the keto diet safe during pregnancy? 

If you’re pregnant, the keto diet is generally not recommended. Some studies suggest that being in ketosis during pregnancy may raise the risk of problems for the baby after birth — including lower IQ. However, the research is limited and conflicting, so more studies are needed to understand the risks. 

Side effects of the keto diet

Switching to a keto diet can cause symptoms for someone who isn’t used to eating this type of diet. Some of these effects are short term. They usually go away within a few weeks after your body gets used to the diet. These symptoms include: 

• Fatigue

• Headaches

• Increased urination

• Dehydration

• Constipation

• Low blood sugar — or hypoglycemia — in people taking certain medications for their diabetes

There aren’t enough long-term studies to know for sure what the risks are of following the keto diet for a longer time period. But some studies have reported that following the keto diet long term may increase the risk of: 

• Fatty liver

• Kidney stones

• Vitamin deficiencies

Can the keto diet reverse diabetes?

It’s possible to reverse diabetes, but it’s not common. One study found that with standard care, diabetes reversal — or remission — is very rare (0.4%). But losing weight and lowering carbs can increase the odds of putting diabetes into remission. 

Whether the keto diet can reverse diabetes is harder to pin down. That’s partly because different studies use different definitions of what “reversal” means, in terms of your A1C levels and whether or not you’re taking medications. A large meta-analysis compared people with diabetes on low-carb or keto diets with those on low-fat diets. Here’s what it found:

• Low-carb and keto diets were more likely to reverse diabetes if the reversal was defined as having an A1C less than 6.5%, even while still taking diabetes medications. 

• But if reversal was defined as A1C less than 6.5% without any medications, the difference between diet groups wasn’t significant. 

• Most studies measured diabetes reversal at 6 months. Only a few studies followed people for 12 months, and those didn’t find a significant difference between groups. 

Why trust our experts?

Written by:

Joanna Jan, MD

Joanna Jan, MD, is board-certified in internal medicine and licensed to practice medicine in the state of Pennsylvania. In 2017, she received her board certification from the American Board of Internal Medicine.

Edited by:

Alex Eastman, PhD, RN

Alex Eastman, PhD, RN, is a California-based registered nurse and staff medical editor at GoodRx, where he focuses on clinical updates and Latino health.

Reviewed by:

Karen Hovav, MD, FAAP

Karen Hovav, MD, FAAP, has more than 15 years of experience as an attending pediatrician. She has worked in a large academic center in an urban city, a small community hospital, a private practice, and an urgent care clinic.

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