Type 2 diabetes is a condition that impacts blood sugar control. A person can manage the condition by following a healthful diet and maintaining a healthy body weight. A ketogenic diet is a high-fat, moderate protein, very low-carbohydrate diet that may help some people in supporting blood sugar.

Some people have suggested that this type of diet might help a person with diabetes, but the American Diabetes Association (ADA) do not recommend any single diet over another.

Every person has different dietary needs. Doctors now individualize diet plans based on current eating habits, preferences, and a target weight or blood sugar level for that person.

Foods containing carbohydrates, such as bread, rice, pasta, milk, and fruit, are the main fuel source for many bodily processes. The body uses insulin to help bring glucose from the blood into the cells for energy.

However, in a person with diabetes, insulin is either absent or does not work properly. This disrupts the body's ability to use carbohydrates effectively and, in turn, causes sugars to be high in the blood.

If a person eats a high-carb meal, this can lead to a spike in blood glucose, especially in a person with diabetes. Diet is important for both type 1 and type 2 diabetes.

Limiting the intake of carbohydrates is the central concept of the keto diet.

Researchers initially developed and continue to recommend the diet for children with epilepsy. However, some reviews maintain that it might also benefit some people with diabetes.

Some research has suggested that following a ketogenic diet might:

  • reduce the risk of diabetes in people who do not yet have it
  • improve glycemic control in people with diabetes
  • help people to lose excess weight

In this article, we look at the possible links between the keto diet and diabetes.

The ketogenic diet severely restricts carbohydrates. It forces the body to break down fats for energy. The process of using fat for energy is called ketosis. It produces a fuel source called ketones.

Impact on blood sugar levels

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The keto diet can help control long-term blood sugar.

A ketogenic diet may help some people with type 2 diabetes because it allows the body to maintain glucose levels at a low but healthy level.

The lower intake of carbohydrates in the diet can help to eliminate large spikes in blood sugar, reducing the need for insulin.

Studies on ketogenic diets, including research from 2018, have found that they can be helpful in controlling levels of HbA1c. This refers to the amount of glucose traveling with hemoglobin in the blood over about 3 months.

Impact on medication

Ketogenic diets may help reduce blood sugar levels. As such, some people with type 2 diabetes who also follow a ketogenic diet may be able to reduce their need for medication.

However, scientists have warned that those following the ketogenic diet alongside an insulin regimen might have a higher risk of developing hypoglycemia (low blood sugar).

Hypoglycemia occurs when blood sugar levels fall to 70 milligrams per deciliter (mg/dL) or less.

It is best to discuss any diet changes with your doctor while on medication. Not consuming enough carbohydrates can be dangerous when taking certain medications for diabetes.

Impact on weight

The ketogenic diet helps the body burn fat. This is beneficial when a person is trying to lose weight, and it may be helpful for people whose excess weight has influenced the development of prediabetes and type 2 diabetes.

Even light-to-moderate weight loss through diet and exercise might support glycemic control, overall well-being, and energy distribution throughout the day in people who have diabetes,

Research has shown that people undertaking a ketogenic diet show an improvement in blood sugar level management and that some have experienced noticeable weight loss.

Benefits

The ketogenic diet can lead to a variety of other benefits including:

  • lower blood pressure
  • improved insulin sensitivity
  • reduced dependency on medication
  • improvements in high-density lipoprotein (HDL), or "good" cholesterol, without adding to low-density lipoprotein (LDL), or "bad" cholesterol
  • a drop in insulin

Meal planning

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Meal planning is vital for people with diabetes.

Ketogenic diets are strict, but they can provide ample nutrition when a person follows them closely and is mindful about meeting nutrient needs.

The idea is to stay away from carbohydrate-rich foods that could spike insulin levels. Typically, the carbohydrate intake on a keto diet ranges from 20–50 grams (g) per day.

To follow the keto diet, people should focus on developing a diet plan that consists of 5–10 percent carbohydrates, 10–20 percent protein, and 70–80 percent fat content. They should avoid processed foods and focus instead on natural foods.

A ketogenic diet should consist of the following types of food:

  • Low-carb vegetables: A good rule of thumb is to eat non-starchy vegetables at every meal. Beware of starchy vegetables, such as potatoes and corn.
  • Eggs: Eggs are low in carbohydrates, as well as being an excellent source of protein.
  • Meats: Fatty meats are acceptable, but should be eaten in moderation to be mindful of heart health. Also, be mindful of consuming too much protein. Combining a high level of protein with low levels of carbohydrates may cause the liver to convert the protein into glucose. This would raise blood sugar levels.
  • Healthful fat sources: These include avocados, olive oil, nuts, and seeds. Although the diet is mostly fat, it is important and recommended to include mostly healthy fats over not as healthy options such as bacon, sausage, red meat, and fried cheeses.
  • Fish: This is a good source of protein.
  • Berries: These are good sources of fiber, vitamins, minerals, and antioxidants that are okay to consume on the keto diet in the right quantity.

One problem with this diet is that it can be hard to follow in the long term.

Learn about putting together an effective diabetes meal plan here.

The ketogenic diet may be a viable glucose management option for some people with type 2 diabetes.

As the ketogenic diet involves switching to a different source of energy, it can lead to some adverse effects.

Short-term side effects

The dietary change might cause symptoms that resemble withdrawal from a substance, such as caffeine.

These symptoms may include:

  • keto-flu, a short-term group of symptoms that resemble those of flu
  • noticeable changes in bowel habits, such as constipation
  • uncomfortable leg cramps
  • a noticeable loss of energy
  • mental fogginess
  • frequent urination
  • headaches
  • loss of salts

In most instances, the side effects are temporary. People often experience no long-term health problems.

Long-term side effects

Long-term effects might include the development of kidney stones and an increased risk of bone fractures due to acidosis.

Other complications include the risk of dyslipidemia and a possible increase in hypoglycemic episodes.

Some animal studies have suggested that, since a low-carb diet often involves additional fat, there might be a higher risk of cardiovascular disease (CVD), due to a buildup of fats in the arteries. People with diabetes already have an increased risk of CVD.

Children may also experience stunted growth, due to reduced levels of an insulin-like growth factor that can lead to bone erosion. This can mean weak bones that are highly susceptible to fractures when a person follows the keto diet.

There is a lack of evidence about the long-term safety and effectiveness of the keto diet, and researchers have called for more primary studies and more evidence before recommending this diet.

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A doctor may recommend a specific meal plan rather than suggesting a diet.

The ketogenic diet is one of many eating plans that might help people manage their weight.

However, a majority of health professionals do not recommend the keto diet for managing diabetes.

There are many other nutrient-dense diets available that aim to balance carbohydrate, protein, and fat intake, control body weight, and keep blood sugar within a healthful range.

Many of these boast measurable benefits for people with diabetes.

Read about the Atkins diet here.

Critics of the ketogenic diet focus on the adverse effects, including the possibility of kidney damage, CVD, and hypoglycemic episodes.

Maintaining this type of diet can also be difficult on a long-term basis, as it is highly restrictive.

This may lead to weight gain later on, particularly if an individual starts to eat unbalanced levels of carbohydrates once they switch back to a regular diet.

Critics also note that there is no evidence to support the long-term benefits of the keto diet.

Health authorities in the United States do not recommend the keto diet as a way to manage diabetes.

It may be better for people to focus on:

  • following a healthful, balanced diet with plenty of fresh fruits and vegetables
  • spread the intake of carbohydrates out evenly throughout the day
  • eat smaller meals more often rather than a large meal once a day
  • follow the advice of the doctor, who will likely recommend a personalized diet plan

A doctor or dietitian can help an individual choose the plan that best fits their lifestyle. People should find a diet that works for them and makes them feel good.

Q:

What should my daily carb intake be?

A:

A daily recommended carbohydrate intake will vary based on many factors including height, weight, medications, genetics, and activity level. People with diabetes should be mindful of not only the number of carbs they eat in one sitting, but also the type.

Sticking with whole-food, nutrient-dense, and fibrous carbohydrates is best for blood sugar management. This includes fruits, vegetables, whole grains, beans, and legumes. Nutrtional experts recommend limiting refined and processed carbohydrates from sweets and sodas.

The number of carbs a person consumes in one sitting will vary. The American Diabetes Association has removed language from their website that specifies a particular number of carbs for people with diabetes for a whole day and per meal.

However, typically, 15–45 grams per meal is a good place to start. Due to the many factors that influence carb needs, it is best to discuss these numbers with a Registered Dietitian Nutritionist for specific and individual recommendations.

Natalie Olsen, RD, LD, ACSM EP-C Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.