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.
Standard Diabetic Education
Maybe you’re not convinced. Maybe you’re leaning toward meeting with the dietitian your doctor has recommended. That’s fine. Many medical professionals are waking up to the potential of the ketogenic diet, so you might actually hear similar advice. Just be aware of what else you might hear.
At three meals and two snacks a day, you’re looking at as many as 240 grams of carbohydrates for a person with diabetes who needs to lose some weight. If you follow the authority-sanctioned “expert.”
I read that and I’m completely blown away. It’s really that bad? That’s what your average type 2 diabetic who shows up at the doctor’s office with no clue about nutrition ends up eating? It’s probably even worse than that, because 60 grams of carbs easily turns into 70.
Perhaps that educator goes on to admit that keto is great for weight loss, has been shown to improve diabetic markers, and could even help prevent diabetes if you could “keep the weight off.” But it’s too hard, too restrictive for most people to follow, she’ll likely suggest.
She claims that the stress of watching how many carbs you eat will be “far more detrimental to your health” than going keto will be beneficial. I don’t actually disagree with that completely. If going keto is so stressful that your every waking moment is consumed by thoughts of carbs, and you can’t stick with the diet no matter how hard you try, maybe it’s not for you. That’s okay. I’ve never said everyone has to go keto, or even that everyone can go keto. Nor have I said that once you go keto, you can’t go back or rotate higher carb days into the routine.
So, good to go?
Mostly. Any medical patient should check with their doctor before changing their diet. You may have to adjust your medications (or remove them entirely). And keeping your doctor involved and apprised of your progress could legitimize the diet—if it works. Your doctor may even start recommending the diet to other patients.
Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.