Here’s the Deal With the Keto Diet and Type 2 Diabetes

Keto can reduce blood sugar, but that doesn’t mean it’s right for everyone
Different dishes representing the keto diet.

Originally created in the 1920s as a treatment for epilepsy, the ketogenic diet (aka “keto diet” or just plain “keto”) is a trending diet that stresses fats and proteins and severely limits carbohydrates and sugars. Because controlling carbs is important to managing Type 2 diabetes, it may seem that keto would be a go-to diet for people living with diabetes.  

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While the keto diet may be effective for some people living with Type 2 diabetes, there’s a lot more to consider, says registered dietitian Melissa Matteo, RD. 

“Managing diabetes with diet truly takes an individualized approach,” Matteo says. “There’s a lot to weigh, in terms of your health needs and your goals. Keto can help some people manage their diabetes, but it’s not right for everyone.”  

We talked with Matteo about the pros and cons of the keto diet for people living with diabetes. Talk with your doctor if you think keto could be right for you.  

Ketosis vs. Ketoacidosis 

When we’re talking about keto and diabetes, there are a few vocabulary words that can get confusing, (especially when they all begin with “keto”). Let’s review a few before we get started: 

  1. Ketones are the fats your body burns when you run out of carb-power. 
  2. Ketosis is the sweet spot you’re looking for when you’re on the keto diet. It means your body has run out of the glucose it gets from carbohydrates and, instead, is burning ketones to create energy.  
  3. Ketoacidosis is when things go too far and ketones build up too much, turning your blood acidic. This is more common for people with Type 1 diabetes when blood sugar levels are too high and insulin levels are inadequate, but it can also happen when you have Type 2 diabetes. Symptoms to look out for include excessive thirst, urinating often, confusion, weakness and fatigue. Diabetes-related ketoacidosis is a dangerous condition. If you think you might be developing it, call your healthcare provider immediately. 

What is the keto diet? 

Glucose (sugar) is the quickest and easiest way for your system to get the energy it needs to go about its business, so your body first turns to the glucose it gets from carbohydrates to fuel up. Carbs are essentially the low-hanging fruit of the metabolic world. (And, yes, many fruits are in fact high in carbs.) 

When there aren’t any carbs hanging around, your body instead turns to fats to get the energy it needs. Converting fats into energy takes more work. So, when your body is running on fats (in a state of ketosis), you’ll burn off more calories. That means you ultimately lose weight because your body is putting in some serious work to keep the juices flowing. 

When you’re on the keto diet, you hyper-restrict foods that contain carbohydrates — including grains and most fruits — and instead load up on proteins and fats (think meats and nuts). This means your body will convert fat into energy instead of gobbling up those easy-to-convert carbohydrates. Keto can lead to rapid weight loss when followed properly. 

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The keto diet’s effects on blood glucose 

By cutting carbohydrate intake to essentially zero, following a strict keto diet has been shown to lower blood sugar levels. For people with diabetes, though, Matteo cautions that low blood sugar should be avoided. 

“For people with diabetes, there is real cause for concern if their blood sugar drops too low,” she says. “Low blood sugar is especially a risk if you’re also on certain diabetes medications or taking insulin.” Monitor your blood sugar levels regularly and speak with your doctor to see if medication adjustments are necessary. 

A blood glucose level that’s lower than the normal range of about 70 milligrams per deciliter is called hypoglycemia. It’s a potentially dangerous condition that can occur, particularly for those living with diabetes, when your food intake and medication levels are out of balance. 

Symptoms of hyperglycemia can include: 

  • Weakness or shaking. 
  • Moist skin or sweating. 
  • Fast heartbeat. 
  • Dizziness. 
  • Confusion. 
  • Unsteadiness. 
  • Nightmares, bad dreams or restless sleep. 
  • Blurred vision. 
  • Headaches and seizures. 

Keto diet and diabetes research 

Scientific research has confirmed the keto diet is effective for managing Type 2 diabetes by lowering blood sugar and promoting weight loss. Researchers also caution, however, that the keto diet can be notoriously difficult to stick with and that research on keto’s long-term effectiveness and risks is still in its early stages.  

Is the ketogenic diet safe for people with diabetes? 

The keto diet can be done safely and effectively for some people living with diabetes. Matteo says determining whether it’s right for you is a question of weighing the pros and cons, and talking with your doctor. 

“Diabetes is a lifelong condition, so managing your diabetes needs to work within your lifestyle,” Matteo notes. “Restrictive meal plans like keto can be effective, but it’s not always the right choice when it comes to sustainability.” 

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Pros 

  • Following a keto diet has been shown to be effective for blood sugar management. 
  • Following a keto diet has been shown to be effective for weight loss. If you have insulin resistance or a BMI (body max index) greater than 30, keto can be an option to get you to your target weight quickly.  
  • If followed in close consultation with your doctor, a keto diet can lead to reduced dependence on diabetes medication and insulin. 

Cons 

  • You may be at an increased risk for hypoglycemia (low blood sugar) while following a keto diet, especially if your medication and insulin aren’t in balance with your eating pattern. 
  • As a severely restrictive diet, keto can be difficult to stick to in the long term. Yo-yo dieting can keep you from developing the long-term healthy habits that will keep your diabetes well managed.  
  • Lack of nutrients while avoiding certain food groups may require supplementation. Speak with your doctor to see if vitamin and mineral supplements are needed. 
  • Constipation may result, as keto eating patterns are often low fiber. Consider low-carb fiber sources or fiber supplements. 

Is keto good for people with diabetes and high cholesterol?  

People with diabetes are already at risk for high cholesterol and heart disease. The keto diet in its purest form might not necessarily distinguish between “good” fats and “bad” fats … but you should. 

“Whether you want to try out keto or follow another carbohydrate-controlled eating pattern, we do stress that your diet should be heart healthy,” Matteo advises. “Because the keto diet is about getting your fuel from fats, your friend who’s doing keto might tell you it’s OK to eat excessive amounts of butter or the fattiest cuts of red meat. We don’t recommend that for anyone.”   

Instead, Matteo suggests people living with diabetes, especially if they also have high cholesterol, should stick with something like the Mediterranean diet, which emphasizes fruits and vegetables, whole grains, beans, nuts and moderate amounts of lean poultry, fish and dairy.   

Matteo also says managing diabetes with diet requires an individualized approach. The best diet to manage your Type 2 diabetes is the one that manages your diabetes, works for your lifestyle and is supported by your doctor.  

“Before you start any restrictive eating pattern on your own, you should talk with your doctor or registered dietitian,” Matteo emphasizes. “They can help you understand your options, advise you on whether any particular diet could benefit you and help you understand any risks.”  

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