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Diabetes and the Ketogenic Diet

There is a great deal of evidence that a keto or very low carb diet can be beneficial to people with type 1 and 2 diabetes as well as prediabetes. But what should you know before embarking on a keto journey?

With Dimitar Marinov MD, PhD and Kristin Gillespie MS, RD, LD, CNSC

Grilling for the keto diet

The ketogenic diet (or keto diet, as it’s nicknamed) has seen rising popularity in the health and wellness communities for a variety of reasons. The diet was actually developed in the 1920s for severe pediatric epilepsy, but today it’s been found to help people lose weight (in the short term) and support health.

Some people in the diabetes community have also used it or some adapted version of it to lose weight, benefit blood sugar and insulin resistance, and to promote overall health.

What is the keto diet?

The keto diet focuses on eating foods that are high in fat, moderate in protein and very low in carbs. While different keto information sources offer varying micronutrient percentage goals, the standard keto diet asks that about 55-70 percent of your daily calories come from fat, while about 25-35 percent come from protein and about five-ten percent (or 50 grams per day in a 2000 kcal per day diet) come from carbohydrates (including carbs from veggies and fruits).

This makes keto fairly restrictive, especially if you’re used to eating more carbs than fat. In short, eating keto requires a major shift in your eating habits.

Also, the standard keto diet focuses on getting you into “ketosis,” which is a metabolic state wherein your body is burning fat (rather than carbs) for energy.

Variations of the keto diet

Aside from the standard keto diet described above, there are a few other variations of the keto diet, including:

  • The cyclical ketogenic diet, which allows for eating 100-150 grams of clean carbs one to two days per week.
  • The targeted ketogenic diet, which follows the same rules but asks you to time when you eat carbs, such as before or after a workout.
  • The very low carb diet (VLCD) approach, which allows people to eat high fat, moderate protein, and very low carbs. Compared to the standard keto diet, this is more generous. It allows for 100-150 grams of carbs daily, versus the standard keto’s 50 grams daily or the cyclical keto’s approach and may not get you into ketosis.

Do you still get the same benefits doing VLCD versus standard keto?

According to Dimitar Marinov MD who also has a PhD in Nutrition and dietetics and is an Assistant Professor at the Department of Hygiene and Epidemiology, and a member of the Medical Faculty of Public Health at MU-Varna, the simple answer is yes.

“You do not require ketosis in order to achieve similar effects, as long as the very low calorie diet is restricting your calories and you are losing weight. The weight loss and stable blood sugar levels are what helps your body lower its insulin resistance.”

A deeper dive into the keto diet’s focus on fat

You might find yourself asking how a diet that focuses on fat could possibly be good for you, especially since many people with diabetes also have obesity. This is a completely reasonable question.

Keto is interesting because it asks us to reframe our understanding of fat. For years, people focused on low-fat foods like milk and yogurt, thinking that fats were the root cause of major health concerns, including obesity. We now know that it is much more complicated.

What changed? It was gradual. For one, a landmark study found that, “The focus on reducing total fat resulted in increased consumption of refined carbohydrates and added sugars, as well as avoidance of nutrient-dense foods rich in healthy unsaturated fats such as nuts, seeds, avocados and vegetable oils.” Only recently are researchers and health providers reversing the anti-fat messaging that wasn’t doing much to keep people healthy. 

In truth, we all need some fat to promote our health — and only recently have we begun de-programming the anti-fatty food stigma in order to embrace high-fat foods.

Simply put, fat is a prime important energy source. It also helps our muscles move, enables our blood to clot, builds cell membranes, and allows your body to absorb the vitamins and minerals you take in. More so, it can help reduce inflammation. For this reason, the keto diet may sound antithetical in nature — but science shows that high fat foods can be healthy and eating lowfat diets can backfire if they cause overconsumption of carbs and processed foods.

What does diabetes have to do with keto?

Diabetes, which is a disease stemming from high blood glucose, affects about 10 percent of the American population. It’s a serious disease that must be treated.

Here’s what you should know about it:

  • In type 1 diabetes, your body doesn’t make any insulin; this is typically diagnosed in childhood and requires lifelong medication.
  • In the more common type 2 diabetes, the body doesn’t make or use insulin properly.
  • People with prediabetes have higher-than-normal blood sugar, but not diabetes which can lead to type 2 diabetes if left unchecked.
  • Gestational diabetes is diabetes that occurs when you are pregnant. It generally resolves after giving birth, but can increase your risk of type 2 diabetes later on.

Because the keto diet is so low in carbs, it may be appealing to people with diabetes. Here’s why:

When you eat carbohydrates, your body breaks them down via the digestive system. If the carbs are digestible, they are turned into sugars, which enter your bloodstream.

The more sugar in your bloodstream, the more need for insulin (which the pancreas produces in healthy people). Insulin is what tells the cells to use the sugar for energy or for energy storage. 

When your cells begin to use the blood sugar, glucagon is released by your pancreas. This hormone tells your body to start storing the blood sugar for energy. The hormones insulin and glucagon work together to make sure you have enough energy.

When you have diabetes, it’s because your body isn’t using insulin properly or can’t make enough (or any) insulin.

How might the keto diet benefit diabetics?

First, it’s important to know that the American Diabetes Association (ADA) doesn’t recommend the keto diet over other diets, and that this diet isn’t a magic cure or silver bullet. It’s important to note, however, that there are many ketogenic diet enthusiasts who claim it can reverse or reduce the impact of diabetes and help with weight loss.

There is limited information on long-term effects, and every patient with diabetes should embrace the keto diet with an individualized, doctor-approved approach (see more below in the ‘warnings for diabetics’ section).

Benefits of keto for diabetes

  • Quick weight loss
  • Lower A1C levels
  • Improved glycemic (or blood sugar) control
  • Lower triglycerides
  • Insulin resistance improvement
  • May reduce need for insulin
  • Increases heart-healthyHDL (or “good”) cholesterol levels
  • Improves cognitive function

Dr. Marinov says the keto diet — as well as very low-carb diets — do show consistent benefits for people with diabetes and prediabetes by vastly improving blood sugar levels and reducing the need for insulin. They also help the weight come off faster than other diets.

A person who is diabetic likely will also experience weight loss on the keto diet, too — which is an added bonus, since weight loss can improve insulin resistance.

“The ketogenic diet helps with insulin resistance in multiple ways: by reducing carbohydrate intake, presence of ketones, and potential weight loss,” says Kristin Gillespie MS, RD, LD, CNSC, and a registered dietitian and certified nutrition support clinician.

In fact, The British Journal of Nutrition found that people using a keto diet dropped and kept off more weight than people on other diets, especially low-fat diets.

Keto is not just about weight loss for diabetics

For Lele Jaro, a type 2 diabetic, weight loss wasn’t the end of the road. She’d decided to try keto in order to better manage her blood sugar — which was still high even after losing 60 pounds. By going keto, she was able to manage her A1C levels, getting them down to six percent from 10 percent. The keto diet actually enabled her to cut down and eventually stop using insulin.

Science backs this up. In a 2018 study published by Diabetes Therapy, a group of 262 people with type 2 diabetes were able to reduce their A1C levels and reduce or eliminate diabetes medication after one year of ketogenic dieting.

Jaro’s tips for other diabetics going keto? Eat whole foods, eliminate snacks, eat healthy fats (but don’t go too wild; if you’re already eating bacon there’s no need to add butter, for example), and prep your meals.

Going keto means making smart choices & not getting discouraged

Remember,  Dr. Marinov says, “The ketogenic diet will only work if it does not provide more calories than the body burns on a daily basis. Usually, completely avoiding carbs creates a large calorie gap which leads to quick weight loss.”

Of course, this weight loss can be motivational, but it doesn’t mean you should overeat fats or sprinkle more unhealthy fats into your diet. He recommends you focus on poly or monounsaturated fats and short-chain fatty acids (think including cheese, butter, pickles) to improve cholesterol and reduce cardiovascular risk.

Also, plateau often sets in — and this can be tough on patients embarking on a health journey. And you should know that it’s normal. “Patients lose motivation and since the diet is very restrictive….” Dr. Marinov says. “...they quit it altogether, which returns them back to the health state where they were to begin with. The solution to this problem is switching from a keto diet to a more balanced low-carb diet, which allows slightly more carbs and thus more variability in dietary options.”

But where smart food choices come into play, there must also be exercise.

According to a review in Nutrients, diet alone isn’t going to improve your health. You’ll need regular movement: “We want to underline that diet and exercise are both vitally important to good health in diabetes,” the review states. “All the exercise in the world will not help you lose weight if your nutrition levels are out of control, but the adoption and maintenance of physical activity are critical for blood glucose management and overall health in individuals with diabetes and prediabetes.”

This is especially important since most people don’t stay in ketosis forever (and there are no studies showing the long-term effect of ketosis). There are also no formal recommendations for how long someone should go keto for, especially if your doctor says you’re healthy. 

Most people go keto for a few months — and then tweak their eating habits afterward. Coming off of it, you’ll want to slowly add carbs back into your diet but integrate a lower-carb approach into your lifestyle going ahead for weight maintenance.

What you should know before going keto

According to a review in the medical journal StatPearls, “The short-term effects (up to 2 years) of the ketogenic diet are well reported and established. However, the long-term health implications are not well known due to limited literature.” In short, its long-term sustainability, safety and efficacy are still not well understood.

There are some short-term side effects to keto, including the “keto flu,” which occurs when your body adjusts to the diet. It may include fatigue, constipation, difficulty sleeping, dizziness, headaches and nausea. The review found that adequate hydration and electrolyte intake are key when trying to prevent these symptoms.

Dr. Marinov also recommends eating green vegetables, mushrooms, avocados and other no-carb but high-fiber options. “These foods will support the body with electrolytes which are often flushed out when you first start a keto and people experience the ‘keto flu.’”

Beyond the keto flu, are some other risks, too, including vitamin and mineral deficiencies, kidney stones, and other health issues. It may also not be suitable for many people, depending on their health status — so be sure to check with a medical provider before embarking on a keto journey!

Warnings for diabetics going keto

According to Anis Rehman MD, Assistant Professor and Associate Program Director of Endocrine, Diabetes and Metabolism Fellowship at Southern Illinois University School of Medicine, keto may pose several risks to diabetes patients. “Diabetes type 1 patients can result in diabetic ketoacidosis, a medical emergency that can be fatal. Diabetes Type 2 patients who are ketosis-prone may also suffer from diabetes ketoacidosis (DKA), which requires hospitalization.”

Here’s what you should know about DKA: When you change from carbs to fats as an energy source, you increase ketones in the blood (this is when your body achieves ketosis, as mentioned earlier).

If you have too many ketones in your blood, you could suffer from diabetic ketoacidosis. This is a dangerous, potentially fatal condition that comes from high blood sugar (or hyperglycemia) and increased acid. As Dr. Rehman says, people with type 1 diabetes are greatly affected by it, although people with type 2 diabetes are also at risk, especially if you are not taking insulin or have uncontrolled blood sugar.

If you are sick while eating a very low carb diet, this could increase your risk of DKA as well. Signs of DKA include breath that smells like fruit, acetone (like nail polish remover), mental slowness, impaired thinking, heavy breathing and acting drunk while sober. You might also experience serious thirst, urination and appetite.

Check your blood sugar levels throughout the day while on the keto diet. You can also ask your doctor to check your ketone levels, especially if your blood sugar is higher than 240 mg/dL.

Your best move? Call your doc. “Diabetes patients should first consult their physician to adjust their diabetes medications and/or insulin regimen to prevent hypoglycemia (or low blood glucose) which can be life-threatening,” says Dr. Rehman.

What about gestational diabetes? It’s important to note that the keto diet and other variations aren’t for pregnant people. According to Dr. Marinov, “The ketogenic diet and VLCD are dangerous for pregnant women, which is why they are not suitable for gestational diabetes.”

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