Using the Ketogenic Diet to Manage Diabetes

Pros, Cons, and Best Practices

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Ask a wide range of experts—doctors, dietitians, and nurses—how they feel about the ketogenic diet for diabetes and you'll probably hear a wide range of answers. Some answers might be based on personal experience, while others are based on scientific evidence—does it work, what are the long-term benefits/risks, etc.

Ask a number of people who have diabetes what they think about it, and you'll also hear a wide range of answers. The reason for this is because no two individuals with diabetes are exactly alike—while this type of dietary approach may work for some, it's not meant for all. Ketogenic diets can serve their purpose, but their rigidity and restrictiveness may make them hard to follow and can result in other health issues (such as elevated cholesterol) if not followed properly. Learn more about the ketogenic diet and the research behind it. 

What Is a Ketogenic Diet? 

The ketogenic diet is a dietary regimen that restricts carbohydrates to very low amounts (typically below 50 grams) and increases fat. The idea is to create a metabolic state of ketosis so that fat can be used for energy as opposed to carbohydrate.

This type of diet plan has been used since the 1920's in treating medical conditions such as epilepsy. Today, the ketogenic diet is being used for a variety of health conditions, including, glioblastoma, dementia, weight management, diabetes, cancer, and even acne. Additionally, athletes have been known to use this plan or variations of this type of plan to increase exercise performance, and lose fat.

Sarah Currie, MS, RD, personal trainer and registered dietitian says, "There is no doubt that the ketogenic diet works for fat loss. And it is medically safe as long as it’s done right. In my experience, people go wrong when they don't ease into this type of eating plan and restrict plant-based vegetables." 

It is important to mention that there are several variations of the ketogenic diet. Some variations recommend eating less than or equal to 30 grams of carbohydrates per day and do not quantify other macronutrients, like, protein and fat. Whereas the standard ketogenic diet is more specific.

Typically, the standard ketogenic diet recommends consuming, 25-50 grams of net carbohydrate per day. People following the standard ketogenic diet aim to consume 60-70 percent of their calories from fat, 20-30 percent from protein, and no more than 5-10 percent from carbohydrate. For someone following an 1800 calorie diet, they would aim to consume 140 grams of fat, 90 grams of protein and 45 grams of carbohydrate daily.

As you can imagine, this type of eating plan can be hard to figure out without guidance from a trained professional. Therefore, it's important to have a very good understanding of how to start the diet and how to continue so that you can do so effectively and safely. 

Ketosis vs. Ketoacidosis

Before considering this type of eating plan people with diabetes should understand the difference between ketoacidosis and ketosis. Ketoacidosis is a potentially life-threatening emergency that occurs when blood sugars rise to dangerous levels, which forces the body to break down fat for fuel and results in a build of ketones.

When too many ketones build up in the body, the blood can become acidic. This condition is more common in those people who have type 1 diabetes because they do not make any insulin. During ketoacidosis, the blood pH is lowered and ketones in the blood can exceed 20 mmol/l.

Unlike ketoacidosis, ketosis means that your body is using fat for fuel and can result in ketones that reach maximum levels of about 7/8 mmol/l with no change in pH. During ketosis, it is suggested that ketones do not exceed these levels because the brain is able to use the ketones for fuel in place of glucose. 

So what does this mean for someone who has diabetes? If done properly and under supervision, most people with diabetes (unless they have kidney issues or established heart disease) can probably safely follow this diet. However, it's always important to discuss with your healthcare professional first. 

Research

The research on the ketogenic diet and diabetes is promising; however, the issue resides in long-term safety and efficacy of the diet. In fact, in the 2018 Standards of Care in Diabetes, the American Diabetes Association reports that studies have shown modest benefits of very low–carbohydrate or ketogenic diets (less than 50-g carbohydrate per day) and that this approach may only be appropriate for short-term implementation (up to 3–4 months) if desired by the patient, as there is little long-term research citing benefits or harm.

Most of the studies assessing the ketogenic diet are based on short-term implementation. For example, in a study, assessing 262 patients for 10 weeks, where patients followed a ketogenic diet that included three-to-five servings of vegetables, moderate protein, and eating fat until they were full (with a focus on fat quality), all participants were able to eliminate at least one diabetes medication, hemoglobin a1c's were reduced, and they achieved a 20 percent reduction in triglycerides. Participants received diabetes and nutrition education and were closely followed by a health coach. Additionally, they reported daily electronic monitoring of blood sugar (so that they could receive medication adjustments). Intervention also included behavior change techniques and group training/peer experience sharing. 

A meta-analysis which analyzed thirteen studies found that individuals assigned to a very low-calorie ketogenic diet (less than 50 grams per day) showed decreased body weight, and diastolic blood pressure as compared to those who ate a low-fat diet comprised of less than 30 percent of calories from fat. Additionally, those following a ketogenic diet had increased levels of good cholesterol (HDL). But, they also had an increase in LDL (bad cholesterol). 

Another meta-analysis which included a total of nine studies with 734 patients with diabetes, found that a low carbohydrate diet had a significant effect on HbA1c levels and significantly reduced triglycerides concentration ( a marker for heart disease). But, the low carbohydrate diet was not associated with decreased level of total cholesterol and LDL cholesterol.

Expert Opinions

If you are thinking about starting the ketogenic diet it is wise not to dive right in. Sarah Currie, MS, RD, says, "If someone is accustomed to eating 200 or more grams of carbohydrate per day and they suddenly drop down to 50 grams or lower, they are going to feel symptomatic and won't stick with it long enough to use fat as fuel. This type of drastic reduction in carbohydrate may work for some people, but can be dangerous for someone who is living with diabetes, particularly if they are not closely managing their blood sugar and medications."

The safest approach to this diet is to make sure you are motivated and ready to change and consult with a physician or registered dietitian to make sure this diet is right for you. Education, support (both peer and professional) is also very important for successful implementation. Additionally, careful blood glucose monitoring and medication management will be particularly important for people who have diabetes. 

Dietitians and certified diabetes educators agree that the type of fats you choose will be important for health and longevity. Because several studies have shown that a low carbohydrate/ketogenic diet can increase bad cholesterol (an independent risk factor for cardiovascular disease), it is important to limit your intake of saturated fats—processed meats, full-fat cheese, butter, cream. It's best to choose unsaturated fats, such as oils, nuts, seeds, avocado. Additionally, aim to adhere to a plant-based approach as much as possible. Some experts go as far as to recommend following a vegan ketogenic diet.

Many experts also recommend detailed food logs while on this diet to assess vitamin and mineral intake. If people are not eating enough vegetables, and calcium-rich foods, they can be at risk for deficiencies and may need counseling about food choices as well as supplementation. 

Risks

The ketogenic diet can cause hypoglycemia (low blood sugar), especially if medications are not monitored properly. Additionally, because the diet is restricted, people may feel socially isolated or establish an unhealthy relationship with food. Therefore it's important to understand the diets limitations and to be willing and ready to take on this type of eating plan. 

If the variation of the ketogenic diet incorporates large amounts of protein, it can put stress on the kidney and may not be appropriate for patients with diabetes who have kidney disease. 

When the diet includes large amounts of saturated fat (butter, cream, processed meats, full-fat cheese) and doesn't include large amounts of plant-based foods, there can be an increased risk in elevating bad cholesterol (LDL), as well as constipation. That's why it's important to increase intake of non-starchy vegetables, nuts, seeds, and lean protein. 

A Word From Verywell

Before starting this type of diet, it's very important to learn how to implement it safely and make sure you are monitored by a health professional, especially if you are taking glucose lowering medications. When formulating a meal plan, it is beneficial to avoid high intakes of saturated fat, high-fat meats like bacon and sausage, full-fat dairy, butter, and cream, as this can increase bad (LDL) cholesterol.

Instead, choose lean protein, chicken, fish, turkey, and focus on incorporating heart-healthy fats—oils, nuts, seeds, nut butter. Additionally, you'll want to include at least three-to-five servings of non-starchy vegetables—this way you'll meet your vitamin and mineral needs.

The verdict as to whether or not this is a long-term diet plan is still out. It might make the most sense, to follow this diet temporarily and expand it after you've achieved your goals. People have found success in adding small amounts of good quality carbohydrates back in after a few months. 

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