A ketogenic diet can significantly improve blood sugar control in people with type 2 diabetes, and major diabetes organizations now recognize it as a viable treatment option. A meta-analysis published in Nature found that keto diets reduced HbA1c by an average of 1.07 percentage points, an effect comparable to what diabetes medications achieve. But the diet carries real trade-offs, particularly around cholesterol, medication interactions, and the difficulty of sticking with it long enough to see lasting results.
How Keto Affects Blood Sugar and Insulin
Type 2 diabetes is fundamentally a problem of insulin resistance: your cells stop responding efficiently to insulin, so blood sugar stays elevated. A ketogenic diet tackles this from two directions. First, by cutting carbohydrates to roughly 20 to 50 grams per day, you dramatically reduce the amount of glucose entering your bloodstream after meals. Second, the metabolic shift into ketosis (where your body burns fat for fuel instead of carbohydrates) appears to improve how sensitive your insulin receptors are, meaning the insulin you do produce works more effectively.
The result is lower, more stable blood sugar throughout the day. Clinical trials consistently show meaningful drops in HbA1c, the three-month average blood sugar marker. The American Diabetes Association, Diabetes Canada, Diabetes Australia, and the U.S. Department of Veterans Affairs all include low-carbohydrate and ketogenic diets as options for managing type 2 diabetes. The ADA specifically notes that reducing carbohydrate intake has the most evidence of any dietary pattern for improving blood sugar control.
Diabetes Remission Is Possible but Hard to Maintain
Some people on very low-carbohydrate diets achieve what’s called diabetes remission, meaning their HbA1c drops below the diabetic threshold without medication. In long-term studies, remission rates reached as high as 62% at the one-year mark. Participants also reduced their dependence on blood sugar-lowering and blood pressure medications.
The catch is sustainability. By year five, remission rates dropped to just 13%. HbA1c levels, which fell substantially in the first year, gradually crept back up and in some studies slightly exceeded baseline values by year five. Weight followed a similar pattern: participants in one major trial lost an average of 12 kilograms in the first year but regained roughly half of it over the following four years, though they still weighed less than when they started.
The primary factor determining whether remission lasts is whether weight loss is maintained. Once carbohydrates are reintroduced or weight creeps back up, blood sugar tends to rise again. Researchers have noted that carbohydrate cravings make long-term adherence genuinely difficult, with some describing the pull toward carbs as having addiction-like characteristics. Studies that tracked compliance found a noticeable decline in diet effectiveness after 12 months, largely because people stopped following the diet as strictly. Regular support, even something as simple as periodic phone check-ins, has been shown to help people stay on track.
What You Actually Eat on Keto for Diabetes
Most clinical studies on keto and type 2 diabetes use a carbohydrate limit of 20 to 50 grams per day. For reference, a single banana has about 27 grams of carbs, so this is a significant restriction. During the initial adaptation phase (typically the first few weeks), some protocols start as low as 20 grams per day before gradually increasing to around 40 grams.
The classic ketogenic diet gets roughly 70 to 90 percent of its calories from fat, with protein making up most of the remainder. In practice, many diabetes-focused protocols use a modified approach: protein is set at about 1.2 to 1.5 grams per kilogram of ideal body weight (roughly 75 to 90 grams per day for most people), carbs stay under 50 grams, and fat fills in the rest. This is less extreme than the 4:1 fat ratio used in epilepsy treatment and more realistic for daily life. A modified Atkins approach, which doesn’t require weighing food or counting calories, is another commonly used version that starts at 10 to 15 grams of carbs per day and eases up to 20.
The Cholesterol Problem
Blood sugar improvements on keto are well documented, but the effect on cholesterol is more complicated and potentially concerning. Triglycerides (a type of blood fat linked to heart disease) typically drop on a ketogenic diet, which is a positive change. HDL cholesterol, the protective kind, often rises.
LDL cholesterol is where things get tricky. Some people experience dramatic increases. A case series documented patients whose average LDL jumped from 129 mg/dL at baseline to 316 mg/dL on a keto diet, with individual readings ranging from 210 to 810 mg/dL. Those are extreme cases, and not everyone responds this way, but the risk is real. Since people with type 2 diabetes already face elevated cardiovascular risk, a surge in LDL deserves close monitoring. If you start a ketogenic diet, getting your lipid panel checked within the first few months is important.
Medication Interactions to Watch For
If you take diabetes medications, starting a ketogenic diet without adjusting them can be dangerous. Because the diet lowers blood sugar so effectively, continuing the same dose of insulin or certain oral medications can cause hypoglycemia (blood sugar dropping too low). Medication reductions should happen under medical supervision.
One particular risk involves a class of diabetes drugs called SGLT2 inhibitors (common brand names include Jardiance, Farxiga, and Invokana). Combining these medications with a ketogenic diet can trigger a rare but serious condition called euglycemic diabetic ketoacidosis. This is a medical emergency where dangerous acid levels build up in your blood even though your blood sugar reads normal, which makes it easy to miss. Case reports have documented this happening, and many prescribing physicians may not be aware of the interaction.
Kidney Health on Keto
A common concern is whether a higher-protein, higher-fat diet damages the kidneys, especially since diabetes is already the leading cause of kidney disease. The evidence is more reassuring than many people expect. Multiple studies in people with mild to moderate kidney disease have found that ketogenic diets either preserved or improved kidney function.
In a two-year randomized trial comparing keto, Mediterranean, and low-fat diets in 322 overweight participants with kidney disease, the ketogenic diet had the greatest beneficial effect on kidney function, particularly in those with more advanced (stage 3) disease, where kidney filtration rate improved by 7.1 points over two years. A separate study of 92 obese participants on a 15-week ketogenic diet found that nearly 28% of those with early kidney disease saw their kidney function improve enough to no longer qualify as having kidney disease at all. A seven-year analysis of 143 patients with type 2 diabetes on a very low-carb ketogenic diet showed significant improvements in kidney filtration markers alongside a 48% diabetes remission rate.
These findings challenge the older assumption that high protein intake harms kidneys. That said, people with severely reduced kidney function (stage 4 or 5) were generally excluded from these studies, so the safety profile in advanced kidney disease is less clear.
How Keto Compares to Other Diets
Keto isn’t the only diet that helps with type 2 diabetes. A Stanford Medicine study comparing keto and Mediterranean diets found that both improved blood sugar control, with HbA1c dropping 9% on keto and 7% on Mediterranean. The researchers noted that while keto had a slight edge in blood sugar outcomes, the Mediterranean diet was easier to maintain over time.
This trade-off captures the central tension of keto for diabetes. It produces stronger short-term metabolic improvements than most other dietary approaches, but its restrictiveness makes it harder to follow indefinitely. For some people, a less extreme carbohydrate reduction that they can actually sustain for years may produce better real-world results than a strict keto protocol they abandon after six months. The best diet for managing type 2 diabetes is ultimately the one that improves your metabolic markers and fits your life well enough that you keep doing it.