Diabetes and the keto diet

One of the top trending diets today is the low-carbohydrate diet; some popular variations you may have heard of include the keto diet, paleo diet, and the Atkins diet. In the 1920s, doctors at the Mayo Clinic developed a specialized dietary plan to treat epilepsy called the ketogenic or keto diet - a diet plan that is very high in fat, moderate in protein, and very low in carbohydrates (carbs).

The typical keto diet consists of roughly 60-85% of calories derived from fat, 5-10% from carbs, and 15-30% from protein. To meet these requirements, followers of the keto diet will need to include fats, such as avocados, oils, nuts and full-fat hard cheeses at each meal and snack, while strictly limiting carb-containing foods, such as grains (including breads, rice, pasta, and cereal), legumes, fruit and some vegetables. There is solid evidence for using the keto diet in the treatment of epileptic seizures. Additionally, the keto diet is being studied to help manage weight, diabetes, and other health conditions. The safety and effectiveness of this eating pattern over the long term, however, still requires further research.

Normally your body runs on energy from glucose (sugar), which is provided from carbs. The goal of the keto diet is to force your body into using fat stores, instead of carbs, for energy. By strictly limiting the amount of carbs you eat (typically less than 50 grams a day), the availability of sugar drops. Your body begins to break down stored fat into substances called ketones. Ketones accumulate in your blood and replace sugar as the primary fuel for the body. This metabolic state is called ketosis. To stay in ketosis, you need to continue to restrict carbs. However, the exact number of carbs that should be limited in the diet varies from person to person. Eating too many carbs or too much protein can prevent ketosis.

Ketosis is the body’s natural response during periods of fasting or when following a strict very low-carb diet. It’s believed that when people without diabetes closely follow the keto diet, ketones should not reach dangerous levels in the blood. This is because the body will use ketones for fuel and make enough insulin (a hormone made by the pancreas that’s needed to move sugar from the blood to the cells) to keep ketones from accumulating to harmful levels. However, when insulin levels are extremely low in people with type 1 diabetes or advanced type 2 diabetes, ketone production can become dangerously high and cause the blood to become acidic. Without enough insulin, the body continues to break down fat to convert into energy. When ketones reach a dangerous level in the blood, it’s called diabetic ketoacidosis (DKA). DKA is an emergency medical situation that can be caused by the lack of insulin or infection.

For many people with type 2 diabetes who are overweight, losing and maintaining a healthy weight is a key part of managing their condition. Studies suggest that following a low-carb diet, such as the keto diet, can aid in short-term weight loss, but it may not be an effective or safe diet option for everyone. The American Diabetes Association (ADA) recommends that people with diabetes or prediabetes should consider individualized nutrition therapy plans as directed by their healthcare provider, rather than choosing a “one-size-fits-all” diet for managing their condition.

What’s more, sustaining the keto diet may be difficult as you must severely restrict carbs and eat significantly more fats. And while research suggests that a keto diet can improve blood sugar control in people with type 2 diabetes, these diets should be approached with caution. One reason is because consuming excess unhealthy fats is a risk factor for cardiovascular (heart) disease and having type 2 diabetes already increases the risk of heart problems. People with type 1 diabetes should also be wary when following the keto diet due to the risk of DKA or hypoglycemia. It is also important to ensure that you are not lacking essential nutrients that may be excluded in restrictive diets. You should discuss the keto diet or any other diet with your healthcare provider before you try it, especially if you’re using any diabetes medications, including insulin. Your healthcare team can help determine which diet may be best with consideration of your other health conditions, cultural background, personal preferences, and access to food sources in addition to many other factors.

Diet is an important part of diabetes treatment and management. Eating a balanced nutritious diet can also help with many other conditions including obesity, high blood pressure, and high cholesterol. By eating healthy, you can manage your health better and help prevent long-term heart or kidney problems that can happen in people with diabetes.

There is no one-size-fits-all diet plan that works for everyone. Work with your doctor, registered dietitian, and diabetes educator to find a sustainable diet plan to meet your preferences, needs, and goals.

Clinically reviewed and updated by Julie McDaniel, MSN, RN, CRNI, May 2022.