Keto? Low Carb? Neither? What Is the Best Diet for Diabetes?

Updated July 2026

For almost every major chronic disease, the best dietary advice is the same: a whole-food, plant-centric diet. It's the eating pattern tied to a lower risk of heart disease, cancer, and dementia, and to longer, healthier lives. Built on beans and legumes, greens, nuts, seeds, fruits, vegetables, and whole grains, it's naturally high in fiber, high in carbohydrates, and relatively low in fat.

Diabetes is the strange exception. For diabetes and prediabetes, the standard advice flips to the opposite — cut the carbs! The more keto-like the better. That contradiction is worth a closer look, because diabetes is the one condition most closely tied to diet in the first place.

Why is the standard diabetes diet the opposite of every other health-promoting diet?

Mostly because it works on the numbers. Low-carb and ketogenic diets have been well documented to lower blood sugar, reduce insulin needs, and bring down HbA1C (a measure of overall longer-term blood sugar control). That evidence is real, and the advice to restrict carbs for people with diabetes and prediabetes is deeply entrenched. But lower numbers are not the same as a cured disease, and that distinction is where the standard approach starts to break down.

Does a low-carb or keto diet actually cure diabetes?

No. Blood sugar, insulin needs, and A1C are symptoms of diabetes, not its cause. The underlying cause is insulin resistance. A ketogenic diet lowers blood sugar mainly by removing the carbohydrates that would otherwise flood a system that can no longer handle them. The readings improve, but the broken metabolism underneath stays broken.

What actually drives insulin resistance?

Fat accumulating where it doesn't belong — in the liver, muscle, and pancreas. Here's a fact that surprises most people: the way researchers reliably create insulin resistance in lab animals is by feeding them a high-fat diet. So an eating pattern high in fat, even one that improves blood sugar readings, can quietly feed the very process that caused the disease. Improving the symptom while worsening the cause is not a good trade.

Why do people on keto diets get a blood sugar spike from a single piece of fruit?

Because their insulin resistance never went away. Someone following a strict ketogenic diet can have a perfect A1C, normal fasting glucose, and real weight loss, and still watch their blood sugar shoot up after eating any meaningful amount of carbohydrate. That spike is the tell. The keto merry-go-round keeps turning: followers blame the carbohydrate, retreat back to high fat, and stay stuck with the same insulin resistance they started with.

Isn't keto a proven medical diet?

It is, but for a very different problem. The ketogenic diet was developed for children with epilepsy that didn't respond to medication. Even in that setting the side effects are considerable — constipation, high cholesterol, hair loss, kidney stones, muscle cramps, poor concentration, stunted growth, thinning bones, heart rhythm changes, and menstrual irregularities among them — and many children can't stay on it. That history is worth remembering before treating keto as the obvious solution for a completely different disease.

So what is the best diet for diabetes?

The same whole-food, plant-based pattern that protects against heart disease, cancer, and dementia is also the most logical foundation for diabetes and prediabetes. It's high in fiber and lower in fat, which supports steady weight loss and lets fat drain out of the liver, muscle, and pancreas — exactly where it has to leave for insulin sensitivity to recover.

I'll be honest about where I sit: I'm a cardiologist, not a diabetologist. I don't manage diabetes directly, and I don't pretend to be an expert in it. But it defies logic that the eating pattern shown to prevent nearly every other chronic disease — including heart disease, the leading cause of death in people with diabetes — would be the one approach people with diabetes are told to avoid.

If you or someone you love is working to get ahead of diabetes, the most durable path is the one that treats the cause, not just the readings on a lab report.

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