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Can a keto diet reverse type 2 diabetes?

Last updated: May 10, 2020 at 7:44PM | - Published on: Dec 11, 2018

Written by Sarah Neidler, PhD

Scientifically Reviewed by Raphael Sirtoli, MSc


The ketogenic diet as a treatment for diabetes

Diabetes is said to be a ‘progressive, chronic’ disease – incurable, in other words. Recently, case reports and clinical studies have accumulated claiming diabetes reversal with a low-carb or ketogenic diet. Many will debate if ‘reversal’ is the right term since adding in sugar and flour will bring their diabetes back. Nevertheless, there remains no doubt that people with diabetes benefit from these kinds of diets [1]. For diabetics, both type 1’s and type 2’s, a well-formulated low-carb or ketogenic diet should be the first line of lifestyle treatment.

Before going deeper into the topic let’s first clarify what diabetes is and how a ketogenic diet is defined.

What’s a keto diet?

A ketogenic diet is very low in carbs, high in fat and moderate in protein. For a weight stable person, no more than 5% of calories should come from carbs, 70-80% from fat and 20-30% from protein. With this macronutrient-distribution, individuals do not rely on glucose as a major source of energy but use fat for fuel instead. Fat is used to produce ketone bodies, which are used for energy or to regulate certain genes. Two ketone bodies circulate in in your blood: Acetoacetate (AcAc) and Beta-hydroxybutyrate (BHB). A third ketone, acetone, is spontaneously created from Acetoacetate. It is not a source of energy but is useful for ketone measurement. Check our ketone measurement guide to learn more.

Because the ketogenic diet replaces carbs with fat, it keeps blood sugar levels low, reduces the need for insulin and has an overall positive effect on insulin signaling. We will describe further down why this is so crucial for diabetics.

What is diabetes?

Diabetes is diagnosed when your fasting blood sugar is above 125 mg/dL or your HbA1c (poor proxy for 3-month average fasting blood sugar) is above 6.5%. However, that’s not what the disease is, that’s just how doctors diagnose it – uncontrolled blood sugars. The disease exists way before you see high and unstable blood sugar levels.

Diabetes is actually a metabolic problem. It’s characterized by the hormone insulin no longer exerting its important actions appropriately. Your cells and tissues don’t ‘hear it knocking’ so to speak. So you produce more and more insulin, which eventually fatigues your pancreas. This deluge of insulin (hyperinsulinemia) you now find yourself bathing in also causes your fat stores to release fat inappropriately. This ultimately swamps your liver with excess fat (energy). To reduce the excess energy, your liver handles starts frantically producing and pumping out lots of blood glucose. This task (gluconeogenesis) is costly and momentarily solves your liver’s crisis of energy excess. The longer-term cost however are serious consequences like high blood sugars, unstable energy levels, damaged tissues (via glycation and ROS), neurodegeneration and worse body composition (with fat usually stored in the wrong places), etc.

There are two different types of diabetes, type 1 and type 2 and they differ in their causes.

Type 1 is an autoimmune disorder where autoantibodies attack the insulin-producing β-cells in the pancreas [2]. As a consequence, type 1 diabetics produce hardly any insulin. They need to inject insulin to cover what’s called their ‘basal insulin’ need. They run into issues when trying to cover their carb intake too, which we’ll get to.

Type 2 is caused by environmental factors leading to increased insulin resistance, like the 3 big dietary factors: sugar, flour and seed oils. To understand what insulin resistance is, let’s first have a look at insulin’s role in the body.

Insulin has 2 main tasks, to cycle fats into and out of your fat stores appropriately and also keep your blood sugars stable [3, 4]. An increase in blood sugar stimulates insulin release in the pancreas. Insulin then binds to insulin receptors, which unlocks glucose channels so that glucose can enter the cells.

The keto diet help to reverse diabetes by allowing your body to rely on fats for energy.

A second important task of insulin is lipid storage [5]. As long as there is dietary glucose entering the bloodstream it will be taken up by the cells with the help of insulin. This also lowers the use of fat as fuel.

As long as insulin is present, fatty acids are stored away, preferentially in adipose tissues. Insulin also suppresses lipolysis, the release of free fatty acids from stored fat. Insulin resistance is the opposite of insulin sensitivity; insulin-sensitive means that cells respond well to a little insulin and insulin resistant means that they need more insulin to respond appropriately.

With increasing insulin resistance, these physiological processes get disturbed. But what causes insulin resistance?

Did you know?

Before the discovery of insulin in 1921, a low-carb diet was the only way to treat diabetes because uncontrolled blood sugar causes organ damage and has dramatic consequences.

Despite the medical progress within almost 100 years, a diabetic’s risk of contracting heart disease has not decreased. In other words: a low carb or ketogenic diet is still the best treatment option for diabetes!

Type 2 diabetics may be on a range of medications that only treat symptoms, have serious side-effects and leave root causes unaddressed. Medications like Metformin may still make sense to use while reversing diabetes with a ketogenic diet. However, most if not all drugs like insulin and sulfonylureas can and should be discontinued. A note of caution though, changing doses or discontinuing medications is something you should do with the help of your doctor (or at the keep them informed).

There are 2 kinds of insulin resistance in a sense. In diabetes, we see pathological (meaning bad) insulin resistance. On a ketogenic diet, we see physiological (meaning normal) insulin resistance.

The ketogenic diet diverts blood sugar preferentially towards your brain and less towards your muscle by making your muscles insulin resistant. So your brain is kept happy with its 30-50% glucose requirements and your muscle can do without the glucose by happily burning away fatty acids. This is normal metabolic flexibility.

In diabetes, you’ve got generalized insulin resistance that is metabolically inflexible, making you a poor fat burner and hyper-reliant on glucose. This is damaging to your cells and organs. It results in glycated tissues and peroxidized fats that essentially age you, increasing your risk of heart disease, cancer and even losing a limb!

Insulin resistance is caused by several mechanisms, one of which is chronically elevated insulin levels. So what increases insulin levels? Mainly sugar. A poor nights sleep can do it too, but sugar is a big one. This can be sugar that is part of our diet or carbohydrates that are broken down to glucose or other simple carbs. Proteins put together with fats can also be converted into sugar, a process called gluconeogenesis. However, it is really the effect of dietary refined sugars and starches (flour) causing blood sugar and insulin spikes (not protein). These insulin spikes from added sugars and flour are then often followed by a blood sugar crash, leading to a sense of discomfort, even sweating, and usually a craving for more high-carb foods.

When we eat this carby kind of food multiple times per day with little time in-between meals, insulin levels are consistently high throughout the day. Over the years, cells react to this constant overflow of glucose and fat by shutting down their insulin receptors. With fewer insulin receptors, cells become less sensitive to the action of insulin. For the same amount of glucose to be taken up, the pancreas has to produce more insulin.

Not only cells that use glucose as fuel become insulin resistant but also chronically inflamed fat cells. When they become insulin resistant, they take up fewer circulating lipids despite high insulin levels. Insulin resistance also increases the release of free fatty acids from fat storage. Free fatty acids in the blood reduce the glucose uptake into muscle cells and further contribute to insulin resistance.

Insulin resistance is often characterized by high triglycerides, as well as a high ratio of triglycerides to HDL-cholesterol.

Another organ that plays an essential role in blood sugar regulation is the liver. It stores excess glucose as glycogen, and when glucose levels are low, glycogen is broken down to provide glucose [6]. This process is regulated by two hormones: insulin and glucagon. Insulin normally promotes glycogen synthesis and interferes with glucose release from the liver.

With increasing insulin resistance, the liver may release glucose despite the presence of insulin. Another mechanism how insulin resistance leads to an increase in blood sugar.

Insulin resistance becomes worse over time, so more and more insulin has to be produced.

At some point, the pancreas is literally burned out and can’t produce enough insulin to keep even basic blood sugar under control, let alone after a high-carb meal. This state is end-stage of type 2 diabetes where insulin injections become necessary [7]. Type 2 diabetics do not produce less insulin than normal, but the insulin resistance increases the need for insulin. A diabetic pancreas is eventually unable to supply this increased demand.

This sounds like a vicious cycle, and it is! More and more insulin is needed, and increased amounts of insulin further exaggerate insulin resistance. Is there a way to escape this cycle?

Good news: yes, there is a way!

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How to escape the vicious cycle with a keto diet

When ever-increasing amounts of insulin aggravate insulin resistance, it only makes sense to keep insulin levels as low as possible. Does this make sense? You may notice that this is the exact opposite of the standard treatment for diabetics. They receive external insulin to overcome the inability of the pancreas to produce sufficient amounts of the hormone.

Because insulin resistance becomes worse over time, diabetics need more and more external insulin over the years.

So how do you keep your insulin low? You have to decrease the need for insulin. Insulin is needed to shuffle glucose, fats, and proteins into the cells, and if we reduce the amount of glucose in the blood, there is less need for insulin.

You might suspect already that a low-carb or ketogenic diet can help a lot – there’s basically no sugar! On a keto diet, we eliminate everything that causes blood sugar spikes. As a consequence, blood sugar is stable and at healthy levels.

List of keto diet food and insulin index.

Insulin is still required, but only in modest amounts. The less insulin is released, the faster it will disappear again. In between meals, there is plenty of time for blood sugar and insulin to come down. Because you rely on fat instead of glucose for energy, you also eat less frequently on a ketogenic diet, giving your cells even more time without exposure to insulin.

You may even fancy trying intermittent fasting, an excellent method to further increase insulin sensitivity. For further details, check our guide about intermittent fasting.

The decreased exposure to insulin restores insulin sensitivity over time, or in different words reduces insulin resistance. This means that cells become responsive to insulin again and less insulin is needed to perform its function.

Can you reverse diabetes type 2 with a ketogenic diet?

The answer to this question is yes. Many advocates of the ketogenic diet say yes because the diet restores insulin sensitivity, and as a consequence, diabetes symptoms disappear. The ketogenic diet allows diabetics to live a normal life and even come off their insulin entirely (if they retain sufficient insulin secretion capacity).

The counter-argument is that diabetes is not reversed because it will come back soon after starting to eat lots of sugar and refined carbs. How much time is soon? It is difficult to say how “soon” diabetes will come back, and the time it takes depends on many factors. It is, however, true that the ketogenic diet does not set the body back to zero and allows for another few decades of unhealthy eating. On the other hand: every adult with a high sugar/high carb history has a high risk of becoming diabetic. It is just a matter of time.

We also need to define “reversible”… that’s not easy. But what matters is that a low-carb or ketogenic diet increases metabolic flexibility and decreases pathological insulin resistance. In so doing it decreases cardiovascular risk factors and improves overall health. Many diabetics don’t even need external insulin or other diabetic medications when following a ketogenic diet.

Are ketogenic diets beneficial for type 1 diabetics?

Type 1 diabetes is not caused by insulin resistance, but it still makes sense to lower the need for insulin. Because type 1 diabetics hardly produce any insulin, they rely on external insulin when following a standard high-carb diet. Through carb restriction, a ketogenic diet decreases the need for insulin. In some type 1 diabetics, their insulin production is sufficient when following a ketogenic diet. Others still need to inject insulin, but much less than on a high-carb diet. Overall, it is much easier to control blood sugar levels with injected insulin on a ketogenic diet because blood glucose raises only mildly after meals.

In fact, a recent survey of the TypeOneGrit Facebook group established the valuable proof-of-principle. Managing type 1 diabetes with a well-formulated ketogenic diet results in astonishingly improved control of blood sugars [8]. In the words of the authors, they say “exceptional control of T1DM without increased risk of adverse events”.

What should a diabetic eat on a keto diet?

The ketogenic diet is by definition ideal for diabetics, no matter if they have type 1 or type 2 diabetes. However, they need to follow it more strictly since it is a real therapy for their disease.

The most important thing that diabetics have to learn is that there is no reason to avoid fat, not even saturated fat. It is not saturated fat that causes arteriosclerosis and heart disease, but an excess of refined carbohydrates like sugar and flour. Seed oils are implicated in the disease although by other mechanisms that involve damaged lipids and mitochondrial toxins.

here is a list of healthy fat sources, avocado, red meat, fish, eggs, coconut, bacon, pistachio, nuts, dark chocolate, olive oils, chees, greek yogourt

Healthy fats are crucial on a ketogenic diet, but people who have been following the official dietary advice don’t know what healthy fats are. In short: all natural fats that you find in fish, meat, nuts, olives, coconut, and full-fat raw dairy products are healthy for diabetics. On the other hand, oxidized seed oils and the trans fats in margarine should be avoided. Learn more about good fats vs bad fats here.

The same is true for meat. You’ve probably been told to avoid red meat when in fact you should not. Meat is an integral part of any diet including the ketogenic diet. There is no reason to avoid it (OK you’re excused if you’ve been bitten by a lone star tick!). The ketogenic diet reduces cardiovascular risk factors and improves the lipid profile by increasing HDL and lowering triglycerides [9,10].

These foods belong to a ketogenic diet:

– All kinds of meat, organ meats, seafood, and fish
– Nuts and seeds
– Vegetables, preferably leafy greens and mushrooms
– Small amounts of low-sugar fruits, such as berries (and even smaller amounts of starchy vegetables like carrots)
– Full-fat dairy products and eggs
– Coconut oil, olive oil, butter, ghee and lard

Starchy foods, all kind of grains and anything that contains refined carbs should be avoided.

Is the keto diet safe for diabetics?

Many people and even some doctors confuse nutritional ketosis with (diabetic) ketoacidosis. Ketoacidosis occurs in uncontrolled diabetes when the pancreas cannot secrete enough insulin to exert its action in cells, so blood glucose levels and blood ketones both skyrocket to dangerously high levels. Ketoacidosis has nothing to do with nutritional ketosis which is when ketones are produced from all the dietary fat you’re relying on and can thus keep your blood sugar levels under control at low and stable levels.

So yes, the ketogenic diet is safe for diabetics. However, they still need to be closely monitored because diabetes medications including insulin, blood pressure, and beta blockers will have to be adjusted down when following a ketogenic diet. Therefore, the diabetic should do this with supervision from a doctor who is up to date with the nutritional literature.

A ketogenic diet for diabetes with Nutrita

With diabetes, the goal is to first lower your insulin levels so that your blood sugar and triglycerides normalize. Nutrita provides you with the insulin index that allows you to avoid the most insulinogenic foods and replace them with nutrient dense options lower on the insulin index. The insulin index alone can be a bit confusing because fish can cause you to secrete quite a bit of insulin, but your body compensates with other hormones like glucagon, unlike what happens when eating a donut or a pizza.

Nutrita combines the insulin index with other measures, such as the keto score that helps you to optimize ketone production and to stay in ketosis on a well-formulated nutrient dense diet. You don’t need to worry about each and every detail as Nutrita gives you a simple green, orange or red light to indicate which foods fit your goals.

Studies backing low-carb/keto diets benefits for diabetics

Low-carbohydrate diet in type 2 diabetes: stable improvement of bodyweight and glycemic control during 44 months follow-up.

23 diabetes patients were put on a low-carb diet with 20% of calories coming from carbs. They were followed for 44 months and the weight, and HbA1c decreased.

Short‐term effects of severe dietary carbohydrate‐restriction advice in Type 2 diabetes—a randomized controlled trial.

102 patients were randomized to follow either a low-carb or a low-fat diet for three months. The weight loss was greater in the low-carb group. The low-carb group also had a greater beneficial effect on total cholesterol and HDL cholesterol.

The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus.

84 obese diabetes patients were randomized to either follow a ketogenic diet (<20 g Carbs/day) or a reduced-calorie, low-glycemic diet (55% calories from carbs, 500 kcal deficit). The ketogenic group had greater improvements in HbA1c, body weight, and HDL cholesterol compared to the low-glycemic group. Diabetes medications were reduced or eliminated in 95.2% of the ketogenic group and 62% of the low-glycemic group.

A low-carbohydrate, ketogenic diet to treat type 2 diabetes.

28 overweight participants with type 2 diabetes were put on a ketogenic diet for 16 weeks. HbA1c, weight and fasting triglycerides decreased significantly. Out of 21 participants who completed the study, 7 discontinued diabetes medications, and 10 reduced the medications.

A Novel Intervention Including Individualized Nutritional Recommendations Reduces Hemoglobin A1c Level, Medication Use, and Weight in Type 2 Diabetes.

238 patients received nutrition counseling and were asked to follow a ketogenic diet for 10 weeks. After 10 weeks, HbA1c decreased significantly. 56.8% reduced or eliminated at least one diabetes medication.

Effectiveness and Safety of a Novel Care Model for the Management of Type 2 Diabetes at 1 Year: An Open-Label, Non-Randomized, Controlled Study.

262 participants were allocated to a ketogenic diet group, and 87 participants were allocated to a usual care group. In the ketogenic diet group, HbA1c, weight and diabetes medications declined significantly. Insulin therapy was reduced or eliminated in 94%.


Type 2 diabetes is not a chronic and progressive disease if one removes the offending factors from their diet, namely sugar, flour and seed oils. This is imperative because it accomplishes two things; it removes the factors causing and exacerbating the disease, as well as replace them with nourishing foods that also regulate appetite. With nourishing food, a stable appetite and having removed the disease factors, this disease will not progress but regress.

Type 1 diabetics, for now, nearly always need some insulin. How much they need and how effective the exogenous insulin is at controlling their blood sugars largely depends on how well they followed a well-formulated low-carb or ketogenic diet. What it comes down to is that the diet allows you to deal with the easier task: covering your basal insulin needs. Off the diet, people are faced with the harder task: covering basal insulin needs + those arising from carby foods.

Diabetes, whether type 1 or 2, are diseases extremely susceptible to the therapeutic level effects of diets that lower insulin. If those diets are also nutrient dense, evolutionarily matched to humans and produce a more generally preferable shift in metabolism, then all the better. This sort of dietary treatment for diabetes holds great promise in their potential for helping out in other diseases like cancer, Parkinson’s and Alzheimer’s disease.

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Written by Sarah Neidler, PhD

Sarah Neidler did her PhD in cancer research at the Beatson Institute for Cancer Research in Glasgow. She has a strong interest in nutrition and the ketogenic diet and believes that they are beneficial for the treatment and prevention of chronic conditions, such as heart disease and diabetes. She loves cooking, reading, sewing, Yoga, and CrossFit.