The ketogenic (keto) diet has become a popular trend among people trying to lose weight. Because this diet greatly limits carbohydrates (carbs), it can have a noticeable effect on the way your body processes sugar and fat. If you have diabetes, you may be wondering if this diet is right for you. But the answer to that question is more complicated than it seems. And the keto diet may not be the best long-term strategy for improving your diabetes. We’ll review the research and what it tells us about the positive and negative ways this particular diet works for people with diabetes.
Does the Keto Diet Help Diabetes?
There is evidence that carbohydrate restriction can improve glycemic control in people with type 2 diabetes. What’s less clear is whether a stricter ketogenic approach is helpful or can be sustained over time.
Studies have shown that low-carb diets can improve blood sugar and hemoglobin A1C (HbA1C or A1C) – a blood test that shows how well you’ve controlled your blood sugar over the past 3 months. For example, one study found that a low-carb diet was more effective than a low-fat diet in controlling blood sugar and lowering A1C. And some study participants were also able to reduce their insulin doses. Another study showed similar results and observed that low-carb diets were more effective at controlling blood sugar and reducing the need for diabetes medications compared to low-calorie diets alone.
It’s important to note, however, that these studies focused on low-carb diets, not specifically ketogenic diets. And ketogenic diets are notoriously difficult to adhere to over the long term. In fact, two large-scale analyses compared stricter (ketogenic) diets to more moderate low-carb diets in people with type 2 diabetes. Both analyses found that in the short term (3 months), stricter carbohydrate restriction led to better glycemic control. However, these results were not sustained in the long term (12 months).
Thus, while the keto diet may initially lead to weight loss and improved blood glucose, it is unclear whether there are any long-term benefits.
Can the Keto Diet Reverse Diabetes?
There is no conclusive evidence that the keto diet reverses diabetes.
A recent meta-analysis of several studies found that after 6 months, the keto diet normalized A1C levels in people still taking diabetes medication. However, this reversal effect was not seen in people who stopped taking the medication. Therefore, it’s hard to say whether this is a case where the keto diet alone actually reversed diabetes. More importantly, the reversal effect was not maintained after 12 months in either group.
Is it Safe for Someone with Diabetes to do the Keto Diet?
For people who are not used to eating this diet, switching to a keto diet may cause symptoms. These symptoms include:
- Increased urination
- Dehydration
- Constipation
- Low blood sugar — or hypoglycemia — in people taking certain medications for their diabetes
If you are taking medication for diabetes, you should discuss this with your doctor before starting a keto diet. They can help you make any medication adjustments to avoid the risk of a drop in blood sugar.
People who may be at risk for serious side effects of ketosis should approach this diet with caution. This is because a state of ketosis can put additional stress on the body’s systems. People who may be particularly sensitive to the keto diet include the following:
- Are pregnant
- Have kidney disease
- Have Type 1 diabetes
If these conditions apply to you, talk to your healthcare provider before trying to transition to a ketogenic diet to make sure it is safe.
Why Might the Keto Diet be Bad for Someone with Diabetes?
In addition to the unpredictable drop in blood sugar, there is concern that the keto diet may not be the best for our overall health in the long run. More research is needed to look at the long-term consequences of a keto diet over several years or even decades. And experts need to study the effects on other diabetes-related health conditions – such as heart disease.
Some studies have shown improvements in markers of heart health – such as cholesterol levels – on the keto diet. But there are also studies that show the opposite effect. A meta-analysis showed that over time, a keto diet may increase LDL cholesterol, which is a risk factor for heart disease. When someone lowers their carbohydrate intake, this translates into increased fat and protein intake to keep the same number of calories in the diet. And in general, a high-fat diet is not recommended for heart health.
Another thing to consider is that high-fat diets – such as keto diets – may negatively affect the way our bodies process carbohydrates. a 1927 study compared people who ate a high-fat diet for only 2 days to people who ate a regular diet. They found that after 2 days, those on a high-fat diet had significantly higher spikes in blood sugar when eating carbohydrates. Other studies have linked high-fat diets to abnormal glucose handling in the body.
Overall, it’s important to consider the long-term effects of a keto diet. When someone drastically reduces their carbohydrate intake, blood sugar can certainly improve. But high blood sugar is a symptom of diabetes. The underlying cause of diabetes is the body’s abnormal processing of carbohydrates. And we still need more research to understand whether the keto diet helps or hurts the process.
The Bottom Line
The keto diet may contribute to glycemic control and weight loss in people with diabetes. But studies don’t consistently show that these effects last over time. And there’s still a lot we don’t know about the long-term effects of a keto diet. But dietary changes can be a powerful tool to help manage diabetes. A more moderate reduction in carbohydrates may be just as beneficial, not to mention more sustainable in the long term. It’s a good idea to discuss any potential dietary changes with your doctor so they can help you make it a safe part of your diabetes treatment plan.
