What are the benefits of low carbohydrate (ketogenic) diets in managing Type 2 Diabetes?
Ketogenic or very low carbohydrate diets are becoming increasingly popular due to their positive effects in weight reduction, improved lipidemia (fat in the blood) and glucose tolerance1. Because of this, low carbohydrate diets are being used in the management of diabetes, with outstanding results.
A systematic review, looking at the effects of using low carbohydrate diets (20-60g carbs/day) for >6mths in people with Type 2 diabetes, showed a significant 0.5% reduction in HbA1c, which was similar to that achieved by using medication2.
When compared again low fat and low GI diets, low carbohydrate diets resulted in superior weight loss, glycaemic control and lipid profile, with a 10% improvement in HDL ‘good’ cholesterol2.
A low caloric intake has also shown overwhelming results in the management of diabetes.
One study recruited 306 individuals with Type 2 diabetes and divided them into two groups. Group one was assigned to 825-853 calories per day for 3-5 months and group two was the control. Findings showed, that at 12 months, almost half (46%) of participants in group one had achieved remission to a non-diabetic state and required no diabetic medication3.
Nutritional ketosis vs diabetic ketoacidosis
When we restrict carbohydrates (<60g/day), our bodies start to utilise our stored carbohydrates (glycogen). Once our glycogen stores are depleted, this brings on a mild form of nutritional ketosis or ‘fat-burning’ where we start to break down fat (either dietary fat or stored body fat) to produce ketones for fuel (average range from 0.6-1.5mmol/L).
Alternatively, diabetic ketoacidosis (DKA) is a life threatening condition that occurs mostly in Type 1 diabetes but occasionally in Type 2 diabetes. Without enough insulin, the body’s cells cannot use carbohydrates (glucose) for energy. The body goes through a similar transition, switching from a ‘carbohydrate burning’ state to a ‘fat burning’ state, however this leads an accumulation of ketones in the blood at a dangerously high concentrations. Symptoms may include abdominal pain, vomiting and dehydration, requiring hospital admission4.
Effects of low calorie/low carbohydrate diets on diabetic medication
For some individuals with Type 2 diabetes, low calorie and low carbohydrate diets have resulted in the reduction/elimination of diabetic medication. This includes both oral hypoglycaemic medication and insulin5.
When commencing a low calorie/low carbohydrate diet, it is important to cease diabetic SGLT2 inhibitor medication such as Jardiance and Forxiga6-7.
These drugs assist in lowering blood sugar levels by causing the kidneys to remove sugar from the body through the urine. They also increase lipolysis and fat oxidation and enhanced ketogenesis. This can result in increased ketone production when following a ketogenic diet and therefore result in the development of DKA.
Although DKA is usually seen alongside high blood sugar levels (>14mmol/L), in a number of cases associated with SGLT2 inhibitors, individuals may present with only a moderately increased blood sugar level (<11mmol/L), which might delay diagnosis and treatment6-7.
It is important to note that SGLT2 inhibitors can continue to cause metabolic acidosis for several days after the cessation of the drug.
Paoli A, Bosco G, Camporesi EM, Mangar D. Ketosis, ketogenic diet and food intake control: a complex relatopnship. Front Psychol. 2015 February; 6(27):1-9.
Ajala O, English O, Pinkney J. Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes. Am J Clin Nutr. 2013;97:505-16.
Lean MEJ, Leslie WS, Barnes AC, Brosnanhan N, Thom G, McCombie L, et al. Primary care-led weight management for remission of type 2 diabetes (DiRECT): an open-label, cluster-randomised trial. The Lancet . 2018 February; 391(10120):541 – 551.
Gosmanov AR, Gosmanova EO, Dillard-Cannon E. Management of adult diabetic ketoacidosis. Diabetes Metab Syndr Obes. 2014;7:255–264.
WestmanEC, Yancy WS, Mavropoulos JC, Marquart M, McDuffie JR. The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus. Nutr Metab. 2008;5:36.
Ogawa, Sakaguchi. Euglycaemic diabetic ketoacidosis induced by SGLT2 inhibitors: possible mechanism and contributing factors. J Diabetes Investig. 2016 March;7(2):135-138.
Kohli J, Goldfarb S. Metabolic acidosis in a patient with type 2 diabetes. Am J Kidney Dis. 2017;69(6);11-13