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Low-carb and ketogenic diets

A variety of low-carb diets exist. Therefore, it is understandable that both professionals and lay people can find the different terminology confusing.

This overview is intended to provide clarity and to highlight the differences between various diets.


To date, all different terms have not been precisely defined. This complicates the evaluation of study results as well as their interpretation and communication.

For now, KetoMed uses the following values (based on a daily energy intake of approx. 2,000 kcal): g KH/day % of calories for


Very Low Carb/Ketogenic:
20 – 50 g < 10% clinical indications

Low Carb:
50 – 130 g ≤ 25% insulin resistance

Moderate Carb:
130 – 225 g 26 – 45% Prevention

High Carb*:

> 225 g > 45%

* recommended e.g. by the German Nutrition Society (DGE) and health insurance companies.

modified according to Feinmanet al., Nutrition 2015

Low-carb, ketogenic or low-carb high-fat (LCHF) diets are all, in different forms, have reduced carbohydrate availability, in relation to the officially applicable dietary recommendations in Austria, Germany and Switzerland. In all the aforementioned diets, the removal of cereals and sugar represents a central element in the diet.

Low Carb diet:
Reviews and key studies


This meta-analysis of 23 studies confirms that a low-carb diet significantly improves weight, waist circumference, systolic and diastolic blood pressure, serum triglycerides, HDL, fasting blood glucose, HbA1c, insulin, and C reactive protein levels. 

Santos FL, Esteves SS, da Costa Pereira A, Yancy Jr WS, Nunes JPL (2012): Systematic review and meta-analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors. Obesity Reviews 13: 1048-1066.

An eloquent presentation of the available evidence supporting the use of carbohydrate restriction for the treatment of type 2 diabetes. 

Feinman RD, Pogozelski WK, Astrup A, Bernstein RK,  Fine EJ, Westman EC, Accurso A, Frassetto L, Gower BA, McFarlane SI, Nielsen JV, Krarup T, Saslow L, Roth KS, Vernon MC, Volek JS, Wilshire GB, Dahlqvist A, Sundberg R, Childers  A, Morrison K, Manninen AH,  Dashti HM, Wood RJ, Wortman J, Worm N (2015): Dietary carbohydrate restriction as the first approach in diabetes management: Critical review and evidence base. Nutrition 31: 11-13

Compared to the historical use of traditional carbohydrate-restrictive therapeutic approaches, the subsequent insulin era, along with medical technological advances, shows an increase in type 2 diabetes and risk of macrovascular and microvascular complications. Only a newer understanding of the importance of postprandial hyperglycemic control is shifting scientific interest toward the health and economic benefits of carbohydrate-restricted diets. 

Lennerz BS, Koutnik AP, Azova S, Wolfsdorf JI, Ludwig DS (2021): Carbohydrate restriction for diabetes: rediscovering centuries old wisdom. J Clin Invest.;131(1):e142246,

Improvements in diabetes medication, risk factors, cardiac function, and performance range after only three weeks on a low-carb diet: this study from a rehabilitation center for overweight type 2 diabetics compared a moderate low-carb diet (LOGI) with the traditionally recommended low-fat, high-carbohydrate diet, both under a moderate aerobic exercise program in a cross-over design. 

von Bibra H, Wulf G, St John Sutton M, Schuster T, Pfützner A, Heilmeyer P (2014): A Low-carbohydrate/high-protein diet improves diastolic cardiac function and the metabolic syndrome in overweight-obese patients with type 2 diabetes. International Journal Cardiology Metabolic & Endocrine 2: 11-18 

In this 2-year follow-up ofdietary pattern, the effects of a) low-fat, limited calories, b) Mediterranean diet, limited calories, c) low-carb, not limited calories, were compared in 322 overweight subjects. The best results for weight loss and lipid profile persisted for the unlimited low-carb diet. 

Shai I, Schwarzfuchs D, Henkin Y, Witkow S, Greenberg I, Golan R, Fraser D, Bolotin A, Vardi H, Tangi-Rozental O, Zuk-Ramot R, Sarusi B, Brickner D, Schwartz Z, Sheiner E, Mark, R, Katorza E, Thiery J, Fiedler GM, Blüher M, Stumvoll M, Stampfer MJ et al (2008): Weight loss with a low carb, Mediterranean, or low fat diet. New Engl J Med 359: 229-241