Ketogenic Diet and Diabetes: What You Need to Know

Keto diets are hot but is keto the way to go if you live with diabetes?

long live bacon signFollowing a ketogenic diet when you have diabetes is more complicated than the grabby headlines would suggest. (Photo: Unsplash, Antonio Barroro)

Ketogenic diets are hot. The high-fat eating plan that emphasizes bacon and butter promises to deliver on rapid weight loss, lower A1C’s, reduced blood pressure, lower lipids, and improved insulin resistance.

So, for people with diabetes, is keto the way to go?

It’s a little complicated.

A true ketogenic diet consists of high fats, moderate proteins, and very-low carbohydrates. Dietary macronutrients are divided into about 55%-60% fat, 30% to 35% protein and 5% to 10% carbohydrates, about 20 to 50 g per day. 1

The diet shifts the body into ketosis—where it burns fat for fuel rather than carbohydrates. The transition can yield some unpleasant side effects, including high cholesterol, kidney stones, bad breath, irritability, “brain fog,” headaches, osteoporosis, and risk of gout. It can also be difficult to maintain.

In addition, people who take insulin, hypoglycemic oral medications, or sodium-glucose cotransporter 2 (SGLT2) inhibitors should proceed with caution due to a potential risk of dangerously low blood sugars or diabetic ketoacidosis (DKA), a buildup of ketones in the blood that causes it to become acidic. 

And it should never be used in people who are pregnant or have renal disease.

Bring on The Bacon?

But what about those promising results?  Joanne Rizzotto, RD, CDE, director of educational services at Joslin Diabetes Center has worked with keto dieters who have been able to reduce or eliminate their medications, or, even reverse their type 2 diabetes.

Yet, while acknowledging these benefits and willing to work with diabetes clients who are already following or considering a keto diet, she still doesn’t recommend the high saturated fat regimen for people with diabetes.

“Since individuals with diabetes are far more apt to have cardiovascular disease or the risk for it a diet high in saturated fat is not something we want to emphasize in the long run,” says Rizzotto. 

While the elimination of simple white carbohydrates  and processed foods can lead to a quick and significant drop in triglycerides, the high saturated fat content of the keto diet can raise your LDL and may modestly raise your HDL, leading to the danger of atherosclerosis says David Becker, MD, a cardiologist at Chestnut Hill Temple Cardiology in Flourtown, Pennsylvania.

“Since so much about diabetes is about cardiovascular disease, if I had diabetes, I wouldn’t do it,” he says.

And yet, those great numbers on the scale are tough to ignore.

“It’s hard to argue with success for patients who have been desperate to lose weight,” he says.

“If it’s a choice between a diet pill or bariatric surgery, I’d recommend trying keto,” he says. “But I’d also make some modifications, counseling people to change from saturated fat to polyunsaturated.”

Flip the Fats?

The 2019 American Diabetes Association’s Standards of Medical Care in Diabetes notes that a low-carbohydrate diet may result in lower blood sugar levels and has the potential to lessen the use of blood sugar lowering medication in those with type 2 diabetes.

In looking at scientific literature that supports the use of keto diets for diabetes, Dr. Becker notes that many studies cover brief periods of time, are sponsored by industry or offer little information on long-term effects of the diet, since they are so limited in scope.

With no studies lasting longer than more than one year suggesting it’s safe, “It’s hard to figure out long-term effects of keto dieting,” says Dr. Becker.

To avoid dangers posed by saturated fat, one strategy for people following a keto diet and living with type 2 diabetes is to replace unhealthy animal fats (such as red meat or processed fats like butter) with healthy mono-unsaturated fats (olive oil, canola oil or other plant-based fats). One of the few long-term studies on low carbohydrate diets and their effects on mortality suggests that low carbohydrate diets favoring animal-derived animal proteins and fats were associated with higher mortality risk, while the opposite was true for plant-based sources. 3

“Keto diets don’t have to be all bacon,” says Dr. Becker. “I tell patients on keto diets that it can be a great way to kickstart weight loss, but now let’s switch to healthier fats.”

He also suggests that people on keto have their lipids checked within 6 to 8 weeks of starting the diet, to “make sure their lipids aren’t going through the roof.”

“This is particularly important for women of menopausal age when LDL’s tend to go up during hormonal changes,” he says. “It’s also a time many women gain more weight and it’s a really bad combination to follow a high saturated fat diet when you are menopausal because your cholesterol can go really high.”

Keto and Type 1

Mixing type 1 diabetes and keto diets can be “really tricky,” says Rizzotto. The ADA agrees, saying that there is not enough current evidence to support a low carbohydrate diet for type 1’s.

One immediate danger is DKA or dangerously low blood sugars.

“When our bodies shifts from burning carbs to burning fat for energy, it can also be depleted of glycogen and it may predispose someone with type 1 to diabetes ketoacidosis,” she says.

“And people taking any oral hypoglycemic agents or insulin need to be careful since it can lead to dangerously low sugars,” he said.

While research on type 1 and keto diets is scarce, a recent article in Pediatrics 5, shows that adults and children who averaged less than 36 grams of carbohydrate a day had improved rates of glucose control and low rates of hypoglycemia and ketoacidosis.

But the authors of the study also warned against changing diabetes management based on these results and called for additional research on the subject.

Seek Help

For people with diabetes, it’s important to let your health care providers know that you’re on a keto diet.

“Tell your doctor about your keto diet,” recommends Dr. Becker. “Many people don't tell their doctors because they suspect their doctor is not going to like it or they’re ashamed. Instead, work with your doctor or nurse practitioner to make the diet healthy for you.”

Rizzotto adds that people with diabetes who decide to go keto need to seek support to figure out when and how to reduce or get off their medications. They also need nutritional support so that they don’t gain back the weight, a common “yo-yo” phenomenon that occurs with any restrictive weight loss plan.

“People are energized when they lose weight, but then they have to re-enter the world of eating,” she says. “So, you want to work with someone who can help you to make your diet less restrictive and avoid any bad eating habits you may have had before. By following strict plans like this, sometimes you never really change those bad habits."

Updated on: August 14, 2019
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