• By Julie Stefanski
  • In 2019
  • January 23, 2019

Very Low Carbohydrate Diets in Diabetes

By Julie Stefanski MEd, RDN, CSSD, LDN, CDE

“What should I eat?”

Hands down, this has to be the number one question people ask when faced with a diagnosis of diabetes.

Over the last fifteen years, the American Diabetes Association (ADA) has recommended that diet recommendations always be individualized for each person with diabetes.  The new 2019 diet guidelines for diabetes published by ADA are no different, “Evidence suggests that there is not an ideal percentage of calories from carbohydrate, protein, and fat for all people with diabetes.”1

A Change to Diabetes Diet Guidelines

A new statement though has been added that may surprise you.  ADA has acknowledged that “…low carbohydrate eating plans may result in improved glycemia and have the potential to reduce antihyperglycemic medications for individuals with type 2 diabetes. As research studies on some low-carbohydrate eating plans generally indicate challenges with long term sustainability, it is important to reassess and individualize meal plan guidance regularly for those interested in this approach.”

If you’re like me, you probably have a lot of people asking you about a ketogenic diet, especially for diabetes.  The ADA has always recognized that controlling carbohydrate intake has the greatest impact on blood sugar levels.  Previously though, the ADA recommended that individuals not decrease their carbohydrate intake lower than 130 grams per day.  You may wonder how ADA defines the “low carbohydrate eating plan” mentioned.  If we look at the studies ADA cited, the research utilized did indeed utilize a ketogenic diet plan.

Research Results

Unlike the public, ADA is above being influenced simply by bacon filled Instagram posts touting keto benefits. The research cited, specifically studies conducted by Virta Health, have shown significant benefits from an extreme reduction in carbohydrate intake.  These studies dropped carbohydrate intake to amounts needed to induce ketosis, typically less than 40 grams of carbohydrate per day.  In one open-label, non-randomized, controlled study, participants restricted their carbohydrate intake to less than 30 grams per day.  Protein intake was calculated at 1.5 grams per kilogram of body weight and patients received continued nutrition counseling and medical support.2

Average Beta-hydroxybutyrate (BHB) levels, a measure of the intensity and presence of ketosis, showed that subjects were mildly ketotic throughout the year of study. Participants were able to lose an average of 13.8 kg.  More importantly, medications prescribed for diabetes were reduced in response to reduced fasting insulin levels and improved insulin resistance. While both HDL and LDL cholesterol increased slightly, serum creatinine, triglyceride levels, CRP (a marker of inflammation), and liver enzymes (ALT, AST, and ALP) all declined.2

Improved Outcomes

A similar study from the same group also validated that insulin requirements decreased and blood glucose levels declined while following a ketogenic diet.  These changes contributed to decreased fasting insulin levels and improved insulin resistance.3  Improvements in insulin resistance, blunted blood sugar effects with a shift to higher fat intake, and increased feelings of satiety with the high fat diet have all been cited as benefits for a very low carb approach.

Not a Good Mix

While the ADA guidelines acknowledge that this approach may be beneficial for some patients, it also echoes a paper by Kalra.  Ketosis is not advisable for patients prescribed Sodium-glucose Cotransporter-2 (SGLT2) Inhibitors such as canagliflozin, dapagliflozin, and empagliflozin. These meds coupled with a ketogenic diet increases the risk of euglycemic diabetic ketoacidosis.4

ADA further warns “This meal plan is not recommended at this time for women who are pregnant or lactating, people with or at risk for disordered eating, or people who have renal disease…”

Effects for Type 1 Diabetes

The new ADA guidelines also advise that the ideal diet for Type 1 diabetes (T1DM) is unknown.  Compelling evidence though is emerging regarding use of very low carb diets not only in T2DM, but also in T1DM.  If you attended FNCE this fall, you can listen to the session The Science of Modified‐Carbohydrate Diets and Application in the Clinic presented by Dr. David S. Ludwig, Professor of Nutrition, Harvard School of Public Health which reviews some of the current research on the use of very low carb diets.

Dr. Ludwig was a co-author on a study published in Pediatrics in 2018. Researchers set out to assess the impact of a very low carbohydrate diet on outcomes such as HbA1c levels, diabetes-related adverse events such as hospitalizations, ketoacidosis, and hypoglycemia in patients with T1DM.5

With an average intake less than 36 grams of carbohydrate per day and made up of about 40% children, what researchers discovered was surprising.  This group of individuals, who support each other through a facebook group called TypeOneGrit, had excellent glycemic control and very few adverse events.  Their reported outcomes were verified through medical records.  Rates of hospitalization and hypoglycemia were extremely low. HbA1c was 5.67% ± 0.66% among the 316 participants.

From this survey group, 97% met the ADA desired glycemic targets with only 1% being hospitalized for ketoacidosis over 12 months!  What I found particularly sad and concerning though, is that many of these individuals stated that they had to go against the medical advice of their endocrinologist or certified diabetes educators in order to implement this way of eating.

How Dietitians Can Help

As dietitians we all recognize the challenges of following an extremely low carbohydrate diet.  If not well-planned and supplemented appropriately, sources of beneficial nutrients such as vitamin C, D, folate, and minerals such as selenium and calcium along with fiber will likely be missing.  Social, emotional, and physical health can be impacted.  But just like any other therapeutic diet, guidance from a registered dietitian can enhance and improve the quality of the nutrition being consumed.  As valid research continues to emerge supporting use of ketogenic diet therapies, it’s important for dietitians to be knowledgeable regarding diet guidelines and pitfalls for those individuals wanting to replicate the success of this research in their own lives.

Julie Stefanski MEd, RDN, CSSD, LDN, CDE is a nutrition content expert for Relias Learning, a continuing education company, owner of Stefanski Nutrition Services and a national media spokesperson for the Academy of Nutrition & Dietetics.  You can check out more of Julie’s thoughts on ketosis in her article Ketosis and Ketoacidosis: They May Be Sisters, but They’re Certainly Not Twins in AADE in Practice.  You can find her on social media @foodhelp123


  1. American Diabetes Association. 5. Lifestyle management: Standards of Medical Care in Diabetes 2019. Diabetes Care. 2019;42(Suppl. 1):S46–S60
  2. McKenzie AL, Hallberg SJ, Creighton BC, et al. A Novel Intervention Including Individualized Nutritional Recommendations Reduces Hemoglobin A1c Level, Medication Use, and Weight in Type 2 Diabetes. JMIR Diabetes. 2017;2(1):e5. doi: 10.2196/diabetes.6981
  3. Hallberg SJ, McKenzie AL, Williams PT. Effectiveness and Safety of a Novel Care Model for the Management of Type 2 Diabetes at 1 Year: An Open-Label, Non-Randomized, Controlled Study. Diabetes Ther. 2018; 9(2):583-612. doi: 10.1007/s13300-018-0373-9.
  4. Kalra S, Jain A, Ved J, Unnikrishnan AG. Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect. Indian J Endocrinol Metab. 2016; 20:725–9.
  5. Lennerz BS, Barton A, Bernstein RK, et al. Management of Type 1 Diabetes With a Very Low-Carbohydrate Diet.  2018; 141(6). pii: e20173349. doi: 10.1542/peds.2017-3349. Epub 2018 May 7.