A ketogenic diet can push type 2 diabetes into remission for some people, but “reverse” is a strong word that deserves some nuance. In the longest published trial on the topic, one-fifth of patients who completed five years of a supervised ketogenic program achieved full remission, defined as an HbA1c below 6.5% without any diabetes medications for at least three months. That’s a meaningful result, but it also means the majority did not fully reverse their diabetes. The diet consistently improves blood sugar control and reduces medication needs, even when full remission doesn’t happen.
What “Remission” Actually Means
Doctors and researchers largely avoid the word “cure” for type 2 diabetes. A 2021 consensus report from major diabetes organizations settled on “remission” as the preferred term, with a specific definition: HbA1c below 6.5%, sustained for at least three months, with no diabetes medications on board. Testing should happen yearly after that, because remission can be lost over time. The underlying metabolic vulnerability doesn’t fully disappear, which is why ongoing monitoring matters.
How Keto Improves Blood Sugar
Type 2 diabetes is fundamentally a problem of insulin resistance. Your cells stop responding efficiently to insulin, so glucose builds up in the blood. A ketogenic diet addresses this from multiple angles.
The most obvious mechanism is simple: when you eat very few carbohydrates, your blood sugar doesn’t spike as much, so your body needs less insulin. Over time, lower and more stable insulin levels allow your cells to become more sensitive to insulin again. A meta-analysis of 13 studies found that this reduction in insulin demand is what drives the improvement in insulin sensitivity.
At a deeper level, ketosis shifts your body’s energy production. Instead of relying on glucose, your cells burn fat and use ketone bodies as fuel. This promotes more efficient energy production in your mitochondria, the power generators inside your cells. Ketone bodies also suppress an inflammatory signaling pathway that plays a direct role in the development of type 2 diabetes. Since chronic inflammation worsens insulin resistance, dialing it down helps break the cycle.
Animal studies reveal additional changes in the liver, which is central to blood sugar regulation. In diabetic mice, a ketogenic diet shut down two key enzymes involved in the liver’s production of new fat. It also increased levels of a hormone that promotes fat burning and improves insulin sensitivity, while decreasing a glucose transport protein linked to excess insulin production. The net effect is a liver that stores less fat and manages glucose more effectively.
How Quickly Blood Sugar Drops
The timeline is faster than most people expect. HbA1c improvements show up within three weeks of starting a ketogenic diet, and the most dramatic changes tend to happen in the first 70 days. One study documented HbA1c dropping from 8.9% to 5.6% in just 90 days. In longer trials, reductions from 7.5% to 5.9% were sustained at 15 months, though most of the improvement appeared early on.
Medication reductions follow a similar pattern. In a one-year follow-up, overall diabetes prescriptions (excluding metformin) dropped from 57% to 30% of participants. All patients on a class of medication called sulfonylureas were able to stop them entirely. Among those using insulin, 94% either reduced or stopped it. In a smaller 15-month study, 8 out of 11 insulin users discontinued it altogether.
The Five-Year Evidence
Short-term results are impressive, but the real question is whether they last. Virta Health published results from a five-year supervised ketogenic program that offer the clearest long-term picture available. One-fifth of patients who completed five years reached full remission. One-third achieved an HbA1c below 6.5% without medications, or with only metformin. And among patients who were on insulin at the start, half no longer needed it at the five-year mark.
These numbers reflect people who stuck with the program. Dropout rates in any long-term dietary study are significant, and sustained carbohydrate restriction is genuinely difficult. The results are real, but they represent what’s possible with consistent adherence and medical supervision, not what happens automatically.
Effects on Cholesterol and Heart Health
A common concern about high-fat diets is their effect on cholesterol. A meta-analysis focused specifically on people with type 2 diabetes found that a very-low-carbohydrate ketogenic diet did not raise total cholesterol, LDL (“bad” cholesterol), or lower HDL (“good” cholesterol) compared to control diets at 3, 6, or 12 months. Triglycerides, a type of blood fat strongly linked to heart disease risk in diabetes, dropped significantly in the first three months, though this difference faded at the 6 and 12 month marks.
This is reassuring, though individual responses vary. Some people do see LDL increases on keto, particularly those who are genetically predisposed to high cholesterol. Lipid monitoring remains important.
What About Type 1 Diabetes?
Type 1 diabetes is a different disease with a different underlying cause: the immune system destroys insulin-producing cells, so the body can’t make its own insulin. A ketogenic diet cannot reverse this. However, emerging evidence suggests it can dramatically improve blood sugar control.
In a published case study, a type 1 diabetic patient following a ketogenic diet reduced total daily insulin needs by 70% and saw HbA1c drop from 7.2% to 5.1%, which is in the normal, non-diabetic range. The patient experienced no episodes of severe low blood sugar or ketoacidosis during the follow-up period. A larger survey of type 1 diabetics eating very low carbohydrate reported a mean HbA1c of 5.67%, with only 2% requiring diabetes-related hospitalizations in the prior year.
Traditional guidelines for type 1 diabetes do not restrict carbohydrates, and the approach requires careful insulin management. The distinction between nutritional ketosis and dangerous diabetic ketoacidosis is important here. Nutritional ketosis produces ketone levels far below the range seen in ketoacidosis (9.8 to 13.7 mmol/L with blood sugars above 476 mg/dL), but medical supervision is essential.
A Serious Safety Concern With SGLT2 Inhibitors
If you take a type of diabetes medication known as an SGLT2 inhibitor (brand names include Jardiance, Farxiga, and Invokana), combining it with a ketogenic diet is dangerous. These drugs, which have become popular for their heart and kidney benefits, carry a rare but serious risk of ketoacidosis at normal blood sugar levels. A ketogenic diet is a known trigger for this reaction.
The FDA has issued warnings about ketoacidosis risk with SGLT2 inhibitors, and published case reports describe this exact combination causing it. Patients taking these medications should not start a ketogenic diet without first discontinuing the drug under medical guidance. If you develop nausea, vomiting, or unusual fatigue while on both, seek medical attention immediately.
Other medication adjustments matter too. Insulin and sulfonylureas typically need to be reduced by about 50% at the start of a ketogenic diet to avoid dangerously low blood sugar. This is not something to manage on your own.
Who Gets the Best Results
People with type 2 diabetes diagnosed more recently, who still have significant insulin-producing capacity, tend to respond best. The longer diabetes has progressed and the more beta cell function has been lost, the harder full remission becomes. Weight loss, which almost always accompanies a ketogenic diet, independently improves insulin sensitivity, making it difficult to separate the effects of ketosis itself from the effects of losing body fat.
Adherence is the single biggest predictor of success. A ketogenic diet typically limits carbohydrates to 20 to 50 grams per day, which eliminates bread, rice, pasta, most fruits, and sugar. People who can sustain this long-term see the best outcomes. Those who cycle on and off tend to see their blood sugar improvements fade. The five-year trial data makes clear that keto is not a short-term fix you can stop once numbers improve. For most people, the metabolic benefits depend on maintaining the dietary pattern.