A modern look at ketogenic diets - indications and health risks

Introduction: The ketogenic diet (KD) is characterized by extremely high fat (F) intake and high carbohydrate (CH) restriction. It is currently used uncontrollably by the population to reduce body weight or body fat.Aim: This article is an attempt to present the biochemical basis of KD and to summarize data regarding both the indications for its use as well as its undesirable effects and contraindications. Special attention is paid to the safety profile of KD.Materials and Methods: Articles, scientific books and publications related to low-carbohydrate diets and KD were searched in the PubMed database and Google Scholar. Articles published in the last decade were included in the review. The search was conducted with a list of keywords: ketogenic diet, safety, obesity, health, mortality.Results: Studies of the effect of KD on obesity showed no difference in appetite control and weight loss compared to other isocaloric (but normal carbohydrate) diets. KDs have many contraindications and create health risks. A meta-analysis of cohort studies finds a link between intake of CHs and overall mortality. The lowest risk of death is observed with the consumption of CHs, providing 50-55% of daily energy intake. Mortality is highest with an intake of CHs below 30%. A relatively higher risk of death was found when CHs on the menu were replaced with animal sources of fats and protein, and lower when replaced with vegetable fats.Conclusion: When switching to KD, it is advisable to choose foods containing mostly unsaturated fats as a priority. It is desirable to avoid sources of saturated fatty acids and, in particular, hydrogenated oils rich in trans isomers of fatty acids. A healthier alternative to the classic KD could be the replacement of CHs with vegetable fats and proteins. This eating pattern can contribute to longevity and good health