Ask the Dietitian: Can the Keto Diet Help with Managing Type 2 Diabetes?

Dear Jillian,

I’ve heard the ketogenic diet can help people with type 2 diabetes manage their blood sugar and improve other aspects of health. Is this true?

— Bezzy Type 2 Diabetes Member

Over the last decade, low carb diets have soared in popularity.

Even though these diets have been linked to a number of health benefits — from weight loss to improved blood fat levels — some people wonder if the very low carb ketogenic diet is safe and effective for people with type 2 diabetes. While following a keto diet can help manage blood sugar, there are less complex and restrictive ways of eating that can have similar benefits.

Let’s break down all about the keto diet and what the science says when it comes to using this diet to manage type 2 diabetes.

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Ketogenic diet overview

The word “keto” gets thrown around a lot in the health and wellness world, but what does it actually mean?

Some people think the ketogenic diet is simply a low carb diet, but this eating pattern is a little more complex. It involves taking in specific amounts of fats, carbs, and proteins in order to shift your body into a metabolic state called ketosis.

When following a ketogenic diet, you’ll need to restrict your carb intake to less than 50 grams per day. This is a very small amount. For example, just one medium banana contains around 26 grams of carbs.

There are a few types of keto diets, but the traditional ketogenic diet is considered a very low carb, high fat, moderate protein diet. It usually consists of 70–80% fat, 15–20% protein, and just 5–10% carbs.

So, you have to significantly restrict carbs while also making sure you’re eating enough fat and not eating too much protein, which could kick you out of ketosis.

When in ketosis, your body breaks down fat to produce molecules called ketones. These ketones are used as an alternate fuel source when carbs are in short supply.

How do you know if you’re in ketosis? Well, the only way to confirm you’re actually in ketosis is to measure ketone levels in your urine or blood using testing strips.

As you can see, following the ketogenic diet is a bit complicated and involves closely monitoring your macronutrient intake to reach and maintain ketosis.

Is the keto diet helpful for people with type 2 diabetes?

Chances are you’ve had a friend, healthcare professional, or family member recommend you try a low carb or ketogenic diet for type 2 diabetes.

This is because low carb and keto diets are heavily promoted in the wellness world as a way to reduce blood sugar and insulin levels and drop excess weight.

But is the keto diet actually worth it when you have type 2 diabetes?

Potential benefits

The keto diet can improve your blood sugar levels. This has been confirmed in dozens of high quality research studies.

A number of research reviews have shown that the ketogenic diet is effective at reducing fasting and post-meal blood sugar levels in people with type 2 diabetes. Plus, it could also help lower hemoglobin A1C (HbA1c), which is a marker for long-term blood sugar control.

The keto diet has also been shown to help improve sensitivity to insulin, the hormone that shuttles blood sugar into your cells.

This makes sense because carbs — which are severely restricted on the keto diet — impact blood sugar and insulin the most. So when you remove high carb foods and opt for foods higher in fat and protein, your blood sugar control will likely improve.

What’s more, the keto diet may help reduce triglyceride levels and body fat in people with type 2 diabetes.

Potential drawbacks

So, if the keto diet can help improve blood sugar management, why not jump on the keto bandwagon?

Well, there are some major issues with the keto diet — especially if you’re interested in adopting a way of eating that you can follow long-term.

First, unless you’re using the ketogenic diet to manage a medical condition like epilepsy or brain cancer, the ketogenic diet is not exactly necessary. Remember, the keto diet involves careful planning and cutting out a number of nutritious foods, so even though it can improve blood sugar management, it’s not recommended for most people.

Research has also shown that the keto diet is extremely difficult to follow long term because of its complexity and restrictiveness.

People following the keto diet must maintain a very low carb intake every single day. This means you’re not able to enjoy higher carb foods — even foods like fresh fruit and starchy vegetables like sweet potatoes — unless carefully planned to fit into your allotted daily carb allowance.

Although the keto diet may work for some people with diabetes, more moderate low carb diets can also be effective for promoting healthy blood sugar management and are much easier to maintain over time.

Another issue with keto diets is that they may negatively affect blood fat levels like LDL cholesterol (“bad” cholesterol) in some people. However, very low carb diets can also have a positive effect on blood lipids like triglycerides and HDL cholesterol (“good” cholesterol), so this relationship isn’t black and white.

Some people may see improvements in heart disease risk factors like cholesterol while following a keto diet, while others may see an increase in certain blood lipids.

Additionally, people transitioning to a keto diet often experience short-term side effects like constipation, nausea, vomiting, and headaches. The keto diet could lead to long-term health issues like fatty liver, kidney stones, and nutrient deficiencies in some people.

Overall, more research is needed to understand how the ketogenic diet affects the health of people with type 2 diabetes over longer time periods and whether it’s more effective than less restrictive low carb diets.

Foods to limit

If you’re interested in transitioning to a ketogenic diet, you’ll have to be mindful of the foods and beverages you consume.

This is because you have to significantly limit carbs in order to reach and maintain ketosis. Some people may be able to reach ketosis when restricting carb intake to less than 50 grams per day, while others may need to restrict carb intake even further.

Because of this, foods that are rich in carbs are off-limits when following a keto diet.

People following a keto diet need to cut out or significantly reduce the following foods:

• Grains: rice, quinoa, oats, etc.
• Starchy veggies and legumes: sweet potatoes, butternut squash, black beans, chickpeas, lentils, etc.
• Bread and bread products: rolls, sliced bread, pizza, bagels, etc.
• Sweets and sweeteners: table sugar, maple syrup, cookies, cupcakes, sugary cereals, donuts, candy, ice cream, etc.
• Fruit and fruit products: apples, raisins, bananas, fruit juice, mango, etc.
• Sugary beverages: soda, fruit juice, chocolate milk, energy drinks, etc.
• Certain alcoholic beverages: beer, mixed drinks with added sweeteners or juice, etc.
• High carb condiments: barbecue sauce, honey mustard, duck sauce, etc.
• High carb snack foods: granola bars, chips, crackers, etc.

Keep in mind that small amounts of lower carb fruits like berries can be enjoyed when following a keto diet as long as your overall carb intake stays under 50 grams per day.

Foods to focus on

When on a keto diet, your focus will be on high fat foods, nonstarchy vegetables, and sources of protein.

• Fats: olive oil, butter, avocados, avocado oil, unsweetened coconut, etc.
• Nonstarchy veggies: cauliflower, broccoli, mixed greens, spinach, kale, onions, zucchini, peppers, asparagus, etc.
• Protein sources: fish, eggs, chicken, red meat, turkey, low carb protein powders, etc.
• High fat dairy: full fat cheese, whole milk yogurt, coconut yogurt, cottage cheese, sour cream, etc.
• Nuts and seeds: walnuts, macadamia nuts, pecans, Brazil nuts, unsweetened macadamia nut butter, pumpkin seeds, etc.
• Low carb fruits (in moderation): blackberries, raspberries, strawberries, lemons, etc.
• Zero carb beverages: herbal tea, black coffee, water, unsweetened sparkling water, etc.
• Keto-friendly packaged foods: keto snack bars, keto crackers, etc.

Remember, just because you’re restricting your carb intake, it doesn’t mean you’re in ketosis. The only way to confirm that you’re in ketosis is to test your urine or blood for ketone levels.

If you’re interested in trying keto, it’s best to work with a healthcare professional like a dietitian to make sure you’re following this complicated diet correctly. A dietitian can make sure you’re consuming the right ratio of macronutrients to reach and maintain ketosis and ensure you’re getting enough nutrients on a daily basis.

So should you try keto if you have type 2 diabetes?

Even though it has been shown to be effective in improving blood sugar regulation, the keto diet is not the best choice for most people with type 2 diabetes.

It’s highly restrictive and complicated to follow — especially long-term — and is usually unnecessary to improve blood sugar management.

Less restrictive low carb diets are generally a better choice because they allow for a greater variety of foods and a higher number of carbs on a daily basis. This means you’ll feel less restricted and will have an easier time meeting your daily nutrient demands.

Low carb diets are defined as diets providing less than 130 grams of carbs per day or less than 26% of your total calories from carbs.

If you’re interested in changing your diet to better manage your blood sugar levels, consider working with a registered dietitian who specializes in diabetes management.

They can help you choose the best eating pattern based on your health history, blood sugar management, body weight, food preferences, and more.

Lastly, you should always consult the doctor who manages your diabetes before making drastic dietary changes. This is especially important if you’re currently using insulin.

The bottom line

The keto diet is a very low carb, high fat way of eating that’s been linked to a few health benefits, including better blood sugar management in people with type 2 diabetes.

Even though the very low carb content of the keto diet may help improve blood sugar levels and some other aspects of health in people with type 2 diabetes, it’s highly restrictive and may not be the best choice for overall health.

If you’re interested in making dietary changes to improve your blood sugar levels, body weight, and more, it’s best to choose an eating pattern that’s easier to follow and tailored to your specific health needs.