Keto Diet and Diabetes

Treatments for diabetes patients have several goals.

The ideal outcome, naturally, is reversal of the disease. But the realistic goals for most patients are to properly manage their blood glucose levels and glycemic control, weight and blood pressure. (1)

Keeping all of those indicators under control can prevent hypoglycemia (dangerously low blood sugar), and the development of serious diseases that commonly develop in diabetics over time.

If those goals ring a bell, it’s probably because you’ve read about an effective way to manage all of them: the low-carb, high-fat diet known as keto.

Studies have shown that the keto diet can effectively lower body weight and body mass, as well as blood glucose, triglycerides and cholesterol levels (all important factors in preventing heart disease), while improving glycemic control. (2)(3)

That would make keto the perfect diet for diabetics, right?

Not always. A keto diet is indeed helpful for most diabetics, but may actually be harmful for some.

Here’s a deeper dive on the subject.

Type 1 vs. Type 2 Diabetes

Research shows that a keto lifestyle has different implications for those with type 1 diabetes, than it does for those with type 2 diabetes. That’s probably because of the big differences between the two types of diabetes.

Type 1 Diabetes

This form of diabetes, which used to be called juvenile diabetes because it’s seen so often in children, is an autoimmune disease. The body attacks the pancreas in type 1 diabetics, leaving it unable to produce insulin.

Insulin helps to move glucose into the body’s cells, so it can be used for energy. When the pancreas can’t produce insulin, a lot of excess glucose (or blood sugar) remains in the blood. And high blood sugar levels are not only the primary indicator of diabetes, they’re the primary cause of more serious diseases that often develop in diabetic patients.

Those with type 1 diabetes can’t be cured, and require regular insulin injections.

Type 2 Diabetes

Type 2 is usually a less-serious form of diabetes in which the pancreas still functions. It can develop for two reasons. Either the pancreas can’t produce enough insulin to meet the body’s needs, or the body’s cells don’t respond properly to insulin. The latter condition is called insulin resistance. In either case, it results in too much glucose in the patient’s blood.

Type 2 diabetes is most common in obese patients (obesity is known to lead to insulin resistance), and it can often be treated with a combination of dietary and lifestyle changes. More serious cases require medication, and some patients do eventually need insulin injections. But in those recently diagnosed and those with so-called “prediabetes,” there are times that diet and exercise can actually reverse type 2 diabetes.

Why Keto May Help Diabetics

There’s been increased research on the high-fat, low-carbohydrate ketogenic diet in recent years, thanks to its popularity and its potential to provide a number of health benefits.

Not all of those supposed benefits have been conclusively proven. But significant weight loss is one effect of keto that’s accepted by most medical authorities. A 2018 review of studies on the subject concluded that a keto diet helped patients lose significant weight in the short term, and that weight loss was greater than on the low-fat diets often prescribed by doctors. (4)

Of course, weight loss could help most diabetic patients, particularly those with type 2 diabetes. But why would keto make more sense for them than other diets? The answer has to do with glucose.

The macronutrient ratios in a standard keto diet (5% carbs, 20% protein, 75% fat) deliberately restrict carbohydrate intake. A shortage of carbs means the body doesn’t have enough “raw material” to convert into glucose for energy. In response, it enters a metabolic state called ketosis, in which it produces ketones as a replacement energy source.

Here’s why that matters for the possible treatment of diabetes. If the body isn’t producing enough glucose to meet its energy needs, there’s obviously much less glucose in the blood than normal.

And since the function of insulin is to help transport glucose, a shortage of insulin (or the inability of cells to use it) is no longer as dangerous for diabetics. They simply don’t have the same need for insulin when there’s much less glucose to transport.

One more thing: when the body’s glucose production is reduced or stopped by the keto diet, a diabetic patient’s blood glucose levels are automatically going to be lower.

So it all makes sense. Keto would seem to be a perfect treatment for diabetes. Does it work that way, though? Let’s look at the research.

Keto and Type 1 Diabetes

Believe it or not, a low-carbohydrate diet was the preferred treatment for type 1 diabetes (T1D), before insulin was discovered 100 years ago.

Since then, treatment for T1D has focused on the use of insulin, combined with healthy, balanced eating plans with low carb consumption. More recently, very limited research has been done on the advisability of specific types of diets for type 1 patients.

Generally speaking, type 1 diabetics appear to experience the same positive results of ketogenic eating as do others on keto. Lower blood glucose levels and better control of cholesterol levels are among them. Most importantly, Hb A1c levels (the measure of blood sugar levels over time) remain consistent, indicating excellent glucose control. (5

The research, however, also shows increased risks for those with type 1 diabetes following the keto diet. The key issue is low glucose (blood sugar) levels: they can get too low if insulin levels aren’t properly monitored and adjusted. Patients experienced a greater number of diabetic ketoacidosis (DKA) incidents, which if untreated can cause serious, life-threatening complications. (DKA is very different than nutritional ketosis, the metabolic state that’s the goal of keto and leads to fat burning and weight loss.)

There are several other possible problems highlighted by the research. Some otherwise healthy and fit type 1 diabetics may lose unnecessary weight on the keto diet, potentially leading to secondary health problems. And the diet has been shown to increase the risk of dyslipidemia, which are elevated levels of LDL (bad cholesterol) and triglycerides that can cause cardiovascular disease and stroke, for patients with type 1 diabetes. (6)

So – is keto safe for those patients? That question can only be answered by your doctor after she evaluates your condition and risk factors. However, it appears to be a good option for patients with well-managed T1D, who carefully monitor their insulin levels and adjust them as necessary. Ketone levels (which show the early signs of DKA) should also be monitored if blood sugar is higher than 240 mg/dL.

Keto and Type 2 Diabetes

The verdict is less complicated for patients with type 2 diabetes mellitus (T2D). The risk of DKA still exists but is much lower. And there’s much more research showing the effectiveness of low-carbohydrate diets, particularly keto, in treating T2D.

A comprehensive review of research on type 2 diabetics who followed a ketogenic diet shows that keto can lead to weight loss, lower cholesterol levels and improvements in insulin sensitivity. (7) One clinical trial showed that in a small group of patients, one-quarter of them were able to discontinue their diabetes medications completely while an even larger group could reduce their meds. Almost all experienced significant weight loss and vastly improved glycemic control. (8)

The bottom line: a keto diet is usually a good choice for type 2 diabetics who must lose weight and body fat, and need better blood sugar control. It may even eliminate or reduce the need for medication. However, it’s still important to consult with a doctor first, and closely monitor glucose levels to avoid side effects or complications.

It’s equally important for all keto dieters to realize that long-term results and risks of the ketogenic diet have not been established. Most medical professionals recommend staying on keto for just a few months. And whether you have diabetes or not, keto is not the best choice if you have thyroid, gallbladder or chronic kidney disease.

Keto vs. Other Diets for Diabetes

So keto is a good eating plan for most diabetics, at least in the short term. But many doctors recommend other diets instead. Are they better than keto?

Some research has been done on the subject, and the keto diet generally wins.

One famous study by Dr. Eric Westman and his colleagues compared keto with the low-glycemic index diet often described for diabetes. Both diets lowered the patients’ weight and glucose levels, but keto patients lost more weight and showed more improvement in their A1c and cholesterol levels. More impressively, nearly all of the keto patients were able to reduce or eliminate their diabetic medications, compared to less than two-thirds of low-GI patients. (9) Proponents of the Atkins diet also claim those same results for Atkins, but the study did not include the higher-carb, later stages of that diet – just the keto-like first stages.

Similar results were shown in a study that compared the keto diet with the low-fat diabetes diet recommended by the American Diabetes Association. Weight loss, lower triglyceride levels and lower A1c results, showing better glycemic control, were all experienced by the keto dieters. (10)

Major research has shown that the olive-oil- and whole-grains-rich Mediterranean diet produces impressive results for diabetics, far superior to those of the low-fat diet just mentioned. (11) Some people are proponents of a very low-calorie diet (which limits food intake instead of placing carbohydrate restrictions) to treat diabetes, which has shown good results. (12) Others tout the “caveman” Paleo diet, backed by controversial supporting research. (13)(14)

However, there is no research specifically comparing the outcomes of any of those meal plans against those of the keto diet in diabetic patients. Experts warn specifically that Paleo dieters run an increased risk of nutritional deficiencies. 

The best idea is to check with your physician and a registered dietitian (who can also help with meal planning), before starting the keto diet, or committing to any specific type of dieting to treat diabetes.