Ketogenic Diet

 By Juan Diego Torres Torres

The ketogenic diet or keto diet is based on a low carbohydrate (5%), moderate protein (5-25%) and high fat (75-90%) intake compared to a healthy and balanced diet in which carbohydrate intake is between 55-60%, protein between 5-25% and fat between 25-30%. The principles of this diet include eating plenty of fruit and vegetables, at least 5 portions (400g) a day. It also includes the consumption of whole grains, nuts and healthy fats rich in unsaturated fatty acids, which should be kept to a minimum (at least 10% of total energy intake). In addition, free sugars should be reduced to less than 10% (50g per day) or 5% (25g per day) of total energy for additional health benefits, and salt intake should be less than 5g per day. This should be accompanied by regular water intake. Thus, in a healthy, balanced diet, the main source of energy is carbohydrate, specifically glucose. On a ketogenic diet, however, the main fuel comes from fats, so the low carbohydrate intake leads to low blood glucose availability, so the body resorts to using fats as fuel. In this way, the low availability of glucose in the blood reduces insulin levels, which in turn reduces the synthesis of fats from glucose, increases fat oxidation and produces an increase in ketone bodies or ketones in the blood, a process called ketosis (from the Latin ketosis). Ketones are metabolites that result from the oxidation of fats and are produced in the liver to fuel skeletal muscle, the brain and the heart, and to maintain normal blood glucose levels. In contrast, on a balanced diet the brain normally uses glucose as fuel, but when blood glucose levels are low, as on the keto diet, the brain can adapt and use ketone bodies or ketones as fuel.

 

The changes in metabolism caused by the ketogenic diet, which are not common in a healthy, balanced diet, can cause certain adverse effects in the short term. These include hypoglycaemia, low blood pH, intestinal problems such as diarrhoea associated with low fibre intake, fatigue, bad breath, headaches, nausea and vomiting. In the medium term, these include hypercholesterolaemia (high LDL or bad cholesterol) when the main source of fat is saturated fat, vitamin, mineral and carnitine deficiency due to low carbohydrate intake, kidney stones (so patients with kidney problems should follow this diet under medical supervision), and predisposition to osteoporosis and fracture problems. These negative effects of the ketogenic diet contrast with the benefits that have been attributed to it in the effective non-pharmacological management of epilepsy in children and adults. Significant and rapid weight loss in the control of overweight and obesity, and in the treatment of diseases such as cancer, Alzheimer's, Parkinson's, polycystic ovarian syndrome, brain damage and acne. This is sometimes not possible with a normal healthy and balanced diet.

According to Maya Vadiveloola, Professor of Nutrition and Food Science at the University of Rhode Island, one of the reasons people choose to go on a keto diet is because they need to lose weight in the short term by eliminating entire food groups, rather than thinking about choosing specific carbohydrates and portion control when eating a balanced diet. For the body to remain in ketosis, carbohydrate intake must be reduced to 10%. Grains, fruit, non-starchy vegetables, many dairy products and even some nuts contain carbohydrates and should be limited. In order to meet these dietary goals, it is common to consume large amounts of high-fat dairy products and fatty meats, while omitting the healthy phytochemicals and fibre from whole grains, fruits and vegetables that are essential to a healthy diet. For this reason, the American Heart Association (AHA) considers the ketogenic diet to be one of the least healthy diets, as it has been shown that people who consume high amounts of fat and inadequate amounts of vegetables, starch and fibre not only raise their blood cholesterol levels, but also alter their blood pressure and increase their risk of cancer, argues Kristina Petersen, professor of nutritional sciences at Texas Tech University in the United States.

The ketogenic diet is currently in vogue for weight loss, although it was originally developed for the treatment of epileptic disorders, as ketone bodies (ketones) produced by this diet have anticonvulsant effects.

The above suggests that society is apparently changing its eating habits towards dietetic ones, focusing more on the purchase and consumption of nutrients than on food, and changing the ideal of a healthy diet to that of an optimal diet that meets all its needs.

References

Cecil, L. (2023, junio 1). La dieta keto podría tener graves consecuencias para la salud. https://www.nationalgeographicla.com/ciencia/2023/05/la-dieta-keto-podria-tener-graves-consecuencias-para-la-salud

Del Castillo, D. & Iriondo-DeHond, A. (2023). Los principios de una dieta saludable. https://www.futurelearn.com/info/courses/nutrition-for-health-spanish/0/steps/281306

InfoAlimentos. (2023). Dieta cetogénica: ¿por qué no es una dieta de moda? https://infoalimentos.org.ar/temas/nutricion-y-estilos-de-vida/506-dieta-cetogenica-por-que-no-es-una-dieta-de-moda

Moreno-Sepúlveda, J. & Capponi, M. (2020). Dieta baja en carbohidratos y dieta cetogénica: impacto en enfermedades metabólicas y reproductivas. Rev Med Chile; 148: 1630-1639. https://scielo.conicyt.cl/pdf/rmc/v148n11/0717-6163-rmc-148-11-1630.pdf

OMS. (2018, agosto 31). Alimentación sana. https://www.who.int/es/news-room/fact-sheets/detail/healthy-diet

Richter, A. (2018). Dieta cetogé. nica: Una guía detallada para principiantes sobre la dieta cetogénica. https://www.healthline.com/health/es/dieta-cetogenica

Reyes, S. & Oyola, M. (2020). Conocimientos sobre alimentación saludable en estudiantes de una universidad pública. Rev. chil. nutr. [online], vol.47, n.1, pp.67-72. ISSN 0717-7518.  http://dx.doi.org/10.4067/S0717-75182020000100067.