Ketogenic diets are low enough in carbohydrate (and protein), and high enough in fat, to encourage the creation of ketone bodies. This creation of ketones resulting from diet is called ‘Nutritional Ketosis’.
Ketogenic diets have a range of applications, from rapid fat-loss, to improved fat use for fuel, and application for many health conditions but some people just don’t benefit from ketogenic diets and it’s likely that your genes determine to a large degree which type of lower-carb diet you should follow. Through trial and error, or by following the tips in The Carbohydrate Appropriate Diet, or Keto-Appropriate Diet Manifesto you can find your best diet.
Your diet should be the most satisfying and comforting that it can possibly be while also allowing you to achieve your physical and mental goals.
What is a low-carb diet anyway?
There is no universally accepted definition for a low-carbohydrate diet and so it can be very confusing for the public (and researchers too!) to know exactly what terms like ‘LCHF’ (low carb high fat) and low-carb, and keto actually mean.
According to researchers low-carb diets contain either:
- 20 and 60 g of carbohydrate (1)
- Up to 200 g of carbohydrate (2)
- Less than the (high) minimum carb recommendation from government bodies (around 45% calories from carbohydrate) (3)
(Confused yet?! )
A review in the journal Diabetes Care gives a much better definition of low-carb diets(4):
- very-low-carbohydrate diet: 21–70 g/day of carbohydrate
- moderately low–carbohydrate diet: 30 to <40% of kcal as carbohydrate
- moderate-carbohydrate diet: 40–65% of kcal as carbohydrate
- high-carbohydrate diet: >65% of kcal as carbohydrate
There is a place for high protein, low carb diets
High protein diets have been a little left out of the conversation around low-carb. Most people recently have been focused on low-carb, high-fat (LCHF) and there is (unjustified) fear around increasing protein intake. When you reduce carbs, you need to replace them with either fat or protein. And high-protein, low-carbohydrate (HPLC) diets have been studied extensively for weight-loss and improving body composition with superior results demonstrated versus high-carbohydrate diets. They have been used to enhance weight-loss with greater loss of body-fat, and reduced loss of muscle along with improved blood markers of health.(5-9)
Increased protein on a low-carb diet can be extremely beneficial, resulting in improved satiety (feelings of satisfaction and fullness from eating) and thermogenesis (calorie burning) when compared to equivalent amounts of either carbohydrates or fat.(10, 11) and here is a higher thermic effect of feeding (TEF) (using more calories) from protein ingestion as compared to either carbohydrate or fat.(12-14)
But, if you are trying to achieve a 'ketogenic' diet, protein can in some cases reduce your ability to achieve nutritional ketosis. A high protein intake can result in higher insulin levels and excess amino acids from protein can be converted to glucose, both of which will limit the creation of ketone fuels. However, the addition of cool, ketogenic supplements like MCT oil, can allow the creation of higher amounts of ketones even if on a higher protein low-carb diet. Diets of this type (higher protein, keto diets) have been shown to increase weight loss and provide more satiety than a in high protein, moderate carb diets.(15) And overall, a higher protein intake hasn't really shown the ability to drastically reduce ketogenesis in most people, most of the time.
So, don't be scared of protein (within reason) on a keto diet homie!
1. Last AR, Wilson SA. Low-carbohydrate diets. Am Fam Physician. 2006;73(11):1951-8.
2. Westman EC, Feinman RD, Mavropoulos JC, Vernon MC, Volek JS, Wortman JA, et al. Low-carbohydrate nutrition and metabolism. The American Journal of Clinical Nutrition. 2007;86(2):276-84.
3. Hu T, Mills KT, Yao L, Demanelis K, Eloustaz M, Yancy WS, et al. Effects of Low-Carbohydrate Diets Versus Low-Fat Diets on Metabolic Risk Factors: A Meta-Analysis of Randomized Controlled Clinical Trials. American Journal of Epidemiology. 2012;176(suppl 7):S44-S54.
4. Wheeler ML, Dunbar SA, Jaacks LM, Karmally W, Mayer-Davis EJ, Wylie-Rosett J, et al. Macronutrients, Food Groups, and Eating Patterns in the Management of Diabetes A systematic review of the literature, 2010. Diabetes care. 2012;35(2):434-45.
5. Layman DK, Baum JI. Dietary Protein Impact on Glycemic Control during Weight Loss. The Journal of Nutrition. 2004;134(4):968S-73S.
6. Layman DK, Boileau RA, Erickson DJ, Painter JE, Shiue H, Sather C, et al. A Reduced Ratio of Dietary Carbohydrate to Protein Improves Body Composition and Blood Lipid Profiles during Weight Loss in Adult Women. The Journal of Nutrition. 2003;133(2):411-7.
7. Piatti PM, Monti LD, Magni F, Fermo I, Baruffaldi L, Nasser R, et al. Hypocaloric high-protein diet improves glucose oxidation and spares lean body mass: Comparison to hypocaloric high-carbohydrate diet. Metabolism. 1994;43(12):1481-7.
8. Farnsworth E, Luscombe ND, Noakes M, Wittert G, Argyiou E, Clifton PM. Effect of a high-protein, energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women. The American Journal of Clinical Nutrition. 2003;78(1):31-9.
9. Labayen I, Diez N, Gonzalez A, Parra D, Martinez J, editors. Effects of protein vs. carbohydrate-rich diets on fuel utilisation in obese women during weight loss. Forum of nutrition; 2002.
10. Keller U. Dietary proteins in obesity and in diabetes. International Journal for Vitamin and Nutrition Research. 2011;81(23):125-33.
11. Halton TL, Hu FB. The Effects of High Protein Diets on Thermogenesis, Satiety and Weight Loss: A Critical Review. Journal of the American College of Nutrition. 2004;23(5):373-85.
12. Westerterp KR. Diet induced thermogenesis. Nutrition & metabolism. 2004;1(1):5.
13. Johnston CS, Day CS, Swan PD. Postprandial Thermogenesis Is Increased 100% on a High-Protein, Low-Fat Diet versus a High-Carbohydrate, Low-Fat Diet in Healthy, Young Women. Journal of the American College of Nutrition. 2002;21(1):55-61.
14. Robinson SM, Jaccard C, Persaud C, Jackson AA, Jequier E, Schutz Y. Protein turnover and thermogenesis in response to high-protein and high-carbohydrate feeding in men. The American Journal of Clinical Nutrition. 1990;52(1):72-80.
15. Johnstone AM, Horgan GW, Murison SD, Bremner DM, Lobley GE. Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum. The American Journal of Clinical Nutrition. 2008;87(1):44-55.