If you think of Type 2 diabetes as carbohydrate intolerance, the natural dietary response should be to restrict the offending dietary component. And when this occurs—when diabetic patients restrict carbs—their symptoms improve, often to a greater degree than diabetic patients on other diets. Keto restricts more carbs than even other low-carb diets, so on the face of things, keto seems great for diabetes.
Let’s take a closer look.
Common Features of Type 2 Diabetes
Insulin resistance: Your cells don’t respond as strongly to insulin, and you need more to produce the desired effect.
Hyperinsulinemia: Your insulin levels are always elevated. This inhibits you from releasing fatty acids from your body fat to be burned for energy.
Hyperglycemia: Because you’re not very good at using insulin to remove glucose from the blood, you often have high blood sugar—especially after eating. In fact, postprandial blood glucose is the most common way to diagnose type 2 diabetes.
Excess body fat: Gaining weight often leads to type 2 diabetes.
Insulin resistance: It depends. Keto can actually induce physiological insulin resistance, whereby the tissues become resistant to insulin so that the small amount of glucose you have in your blood is diverted to the areas of the brain that can’t use ketones. This is normal, not pathological, and doesn’t lead to hyperinsulinemia. If you’re losing weight on keto, your insulin sensitivity will improve.
Hyperinsulinemia: Keto lowers insulin levels. For ketosis to even occur, insulin must be low.
Hyperglycemia: It’s hard to spike blood sugar when you’re not eating carbs.
Excess body weight: Keto is an effective way to lose weight.
So far, so good. Theoretically, keto should work really well for people with type 2 diabetes. How does it work in real life folks with type 2 diabetes, though?
What Studies Tell Us
Study #1: Keto (No Control)
In 2005, researchers gathered 28 overweight patients with type 2 diabetes and placed them on a ketogenic diet with fewer than 20 g of carbs per day. Seven patients dropped out; 21 completed the 16-week study. Those who completed it had great results:
Body weight dropped by 6.6%, almost 20 pounds.
HbA1c dropped by 16%.
Triglycerides dropped by 42%.
Ten patients reduced their medications. Seven dropped them entirely. In only 16 weeks.
This was a pilot study without a control group, so it can’t be cited to directly compare keto to other diets. But it clearly worked.
Study #2: Low-Glycemic vs. Keto (Patients Who Were Obese and Had Type 2 Diabetes)
In another study, researchers directly compared keto to low-glycemic/carb. They took 84 obese patients with type 2 diabetes, randomly assigned them to either a ketogenic diet or a low-glycemic diet, and tracked their progress over 24 months. What happened?
16% reduction in fasting glucose
6.9 kg bodyweight loss
0.5 reduction in HbA1c
20% reduction in fasting glucose
11.1 kg bodyweight loss
1.5 reduction in HbA1c
Both groups improved, but the keto group made bigger improvements, especially in HbA1c. Low-carb is good, keto might be better.
Study #3: Low-Calorie vs. Keto (Patients Who Were Obese)
Another study compared keto to low-calorie in obese patients, about a third of whom had diabetes. This time, the patients got to choose the diet that most appealed to them. So, it wasn’t random, but it was closer to how diets work in the real world.
Both groups improved markers of glucose control and metabolic health, but theketo group saw greater improvements on every single marker measured:
The drop in blood glucose in the keto dieters was intense enough that the researchers recommended anyone interested in trying it retain medical supervision.
In addition, only among the keto group were patients able to discontinue medications.
Study #4: Hypocaloric vs. Keto (Patients with Type 2 Diabetes)
In 2016, researchers ran a four month study comparing the effects of two diets in patients with type 2 diabetes. The first diet was your standard hypocaloric approach. The second was a very low carb ketogenic diet.
The keto group lost more body weight, more inches off their waist, and gained better control over their blood sugar. There were no adverse effects; kidney function remained stable throughout the study. Most importantly, the keto group had no trouble staying on the diet.
Is Keto a “Cure” For Type 2 Diabetes?
Ultimately, it all depends how you define “cure.”
Can you just stop doing everything that led you to resolution of the symptoms and hope the benefits will “stick”? No.
Can you be entirely sedentary and metabolize glucose like a 15 year-old? No.
If you go back to the lifestyle that helped you develop type 2 diabetes, you’ll probably re-develop type 2 diabetes. Maybe it’ll take longer. But there’s no reason to believe the end result will change.
But can you eat slightly more carbs, particularly if you time them with your intense workouts to upregulate insulin sensitivity? Most likely.
Will you be more insulin sensitive just by virtue of having lost all that extra weight? Yes, and it won’t go away as long as you keep the weight off.
That said, this isn’t a cure like antibiotics are a cure for a bacterial infection. You don’t pop a pill, kill the infection, and go back to normal. The cure is ongoing. The therapy never ends.
There’s likely some genetic proclivity happening here—many type 2 diabetics come from a long line of type 2 diabetics. If so, you’re always going to be susceptible. You’ll always have to take those extra steps to keep insulin sensitivity high, whether by making sure to eat your carbs in and around workouts, spending more time keto, religiously optimizing your sleep and circadian rhythm, and doing “everything right.”
However, if you can eat slightly more carbs while maintaining your body weight, that’s a good indicator that you’re not worsening insulin or blood glucose levels. Another good indicator is actually tracking your blood sugar, which I would recommend you do as you increase carbs.
Type 2 diabetes isn’t an on/off switch. It’s a spectrum, and it’s important to know we’re always somewhere on it.
Any medical patient should check with their doctor before changing their diet. You will likely need to adjust your medications (or be able to remove them entirely). Keeping your doctor involved and apprised of your progress offers helpful experience to your physician as well as essential information to you. Your example will speak to the legitimacy of the keto diet. Your doctor may even start recommending keto to other patients.
To sum up, going keto can be an effective dietary strategy for type 2 diabetes. All the available evidence suggests that, as a general guideline, it’s both safe and effective.