Low-Carb Diets. Don’t throw out the baby protein, with the bathwater!

By Cliff Harvey ND, Dip.Fit, PhD (c)

Most people think of ketogenic diets when they think ‘low carb’. 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, you can find your best diet. This 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?

There is no universally accepted definition of a low-carbohydrate diet and so it can be very confusing for the public (and researchers too!) to know exactly what is being spoken about when people use terms like ‘LCHF’ (low carb high fat) and low-carb.

It has been suggested that LCDs contain between 20 and 60 g of carbohydrate.1 On the other hand, it’s also been suggested that anything up to 200 g of carbohydrate is ‘low-carb’!2

Confused yet?!

Often, anything less than the (high) minimum carb recommendation from government bodies (around 45% calories from carbohydrate) is used as the definition for low carb.3 A review in the journal Diabetes Care gives a much better definition of low-carb diets4:

  • 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

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 even some fear around increasing protein intake (which is probably unjustified). 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 There 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 ketosis (either to drastically increase fat loss or to benefit a health condition), 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, coconut oil, and maybe even Apple Cider Vinegar (yep – you read that right!) 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 an in high protein, moderate carb diets.15



  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.

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