The Ketogenic diet, also known as the VLCD (very low carbohydrate diet, 20 – 50g / day), have been around from at least the early 1900’s when it was discovered that it was effective in the treatment of epilepsy in children. It is still being used for that purpose, but more recently this diet has gained its popularity for the management of type 2 Diabetes Mellitus and obesity. It is important to know that the macronutrient ratios and recommendations for the ketogenic diet in the management of pediatric epilepsy (e.g. 80-90% calories from fat and a ratio of fat: protein + carbohydrate combined of 3:1 to 4:1) are substantially different than those advocated for the management of obesity and type 2 diabetes. Evidence-based protocols for the use of the Ketogenic diet in the management of type 2 diabetes and obesity hasn’t been put in place as yet.
How does the Ketogenic diet work?
The purpose of this very low carbohydrate diet is to transition the body from predominantly using glucose to using a higher proportion of fat and amino acids for energy and putting the body into a state of physiological ketosis. Ketosis occurs as follows: insulin activates enzymes in pathways that store energy from carbohydrates; when there is less carbohydrate available, less insulin is required, which leads to a reduction of lipogenesis (the storage of fat) and fat accumulation. After about three days of fasting or drastically reduced carbohydrate intake (less 50 g/day), glucose reserves become insufficient for the supply of glucose to the central nervous system (CNS). The CNS must then find an alternative energy source that comes from one of two places – glucose derived from gluconeogenesis (generation of glucose from fat and amino acids) or from the overproduction of acetyl-CoA due to high fatty acid oxidation, which leads to higher than normal levels of ketone bodies, referred to as ketogenesis. When the concentration of ketone bodies reaches about the same concentration as glucose (about 4 mmol/L), the CNS can use ketone bodies as an energy source. It takes about three days of being in ketosis for the brain to fully adapt to ketones as energy and for muscle degradation to stop.
Limiting carbohydrates and stacking up on fats is not the primary focus of the Ketogenic diet. To maintain a state of Ketosis, the diet should be carefully planned and followed strictly as even too much protein can stimulate glucose production through gluconeogenesis and inhibit the ability for the body to move into ketosis. Generally, on the ketogenic diet, the macronutrient ratio varies within the following ranges:
65-80% of calories from fat
20-25% of calories from protein
5-10% of calories from net carbohydrate.
Nutrients of particular concern on the ketogenic diet are calcium, vitamin D, selenium, magnesium, zinc and phosphorus. When planning a Ketogenic diet, selecting nutrient-rich food is important to prevent potential nutrient deficiencies.
Another note of importance; it is not recommended for someone who has followed the Ketogenic diet of less than 50g carbohydrate / day to immediately switch to a normal diet with about 130g carbohydrates / day. Transition should be gradual with an increase of about 10 – 15 g carbohydrates per day.
Tips for if you are following a Ketogenic diet or if you are considering it:
- This is not a “self-help” type of diet. Seek professional help as you might be doing more harm than good if you are not doing it correctly.
- The Ketogenic diet is NOT for everyone. Please speak to your doctor before considering this diet.
- Avoid all processed food as far as possible when following this diet. Some individuals see this diet as the opportunity to have highly processed meat which may be harmful to your health if consumed in large amounts. READ LABELS!!!
- Rather have nutrient-rich foods such as salmon, sardines, mackerel and other fatty fish are very high in omega-3 fats, low-carb vegetables (peppers, spinach, broccoli, and cauliflower, zucchini), avocado, plain yoghurt and cottage cheese, olives and olive oil, nuts and seeds, and berries.
- Ask yourself: IS THIS DIET SUSTAINABLE?
The take-home message and something to think about before taking on any diet out there: Any type of diet that you take on, whether it is cutting out any food group, focusing on a specific way of eating, whether it is a diet based on liquids, whatsoever, it will take courage and perseverance. To follow a balanced healthy lifestyle also takes courage and perseverance. Whatever you take on…just make sure that it is sustainable and doesn’t harm your health in the long-term.
A huge thanks to Melissa Ludick for the contribution. For appointments with Melissa, please contact our reception.
Dietitians of Canada. Nervous System – Pediatric/Paediatric Epilepsy: Ketogenic Diet. In: Practice-based Evidence in Nutrition® [PEN]; 2014 Jul 29. Available from: www.pennutrition.com. Access only by subscription. Free trial available.
Gupta L, Khandelwal D, Kalra S, Gupta P, Dutta D, Aggarwal S. Ketogenic diet in endocrine disorders: Current perspectives. J Postgrad Med. 2017 Oct-Dec;63(4):242-51. doi: 10.4103/jpgm.JPGM_16_17. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/29022562
Paoli A, Rubini A, Volek JS, Grimaldi KA. Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets. Eur J Clin Nutr. 2013 Aug;67(8):789-96. doi: 10.1038/ejcn.2013.116. Epub 2013 Jun 26. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/23801097
Gershuni VM, Yan SL, Medici V. Nutritional ketosis for weight management and reversal of metabolic syndrome. Curr Nutr Rep. 2018 Sep;7(3):97-106. doi: 10.1007/s13668-018-0235-0. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/30128963