The ketogenic (keto) diet

The ketogenic (keto) diet is a very low-carbohydrate, moderate-protein, and high-healthy-fat eating pattern. It was developed in the 1920s to treat refractory epilepsy in children (Mayo Clinic) and gained popularity in the US from 2018 onwards as a rapid weight loss strategy.
The Central Mechanism: The State of Ketosis
The fundamental principle of the keto diet is to induce a metabolic state called nutritional ketosis.
Carbohydrate Restriction: In a normal diet, glucose (derived from carbohydrates) is the body’s and, primarily, the brain’s main source of energy.
Metabolic Adaptation: With carbohydrate intake reduced to a very low level (usually between 20g and 50g per day), the body depletes its glycogen reserves. As a survival mechanism, the liver begins to break down fats (lipolysis) and produce molecules called ketone bodies (mainly β-hydroxybutyrate and acetoacetate).

Ketone Bodies as Fuel: These ketones become an alternative energy source, a “high-octane fuel” for most tissues, including the brain, characterizing the state of ketosis.

How Ketosis Works in the Body
Under normal conditions, glucose is the main energy source. When glucose levels decrease due to low carbohydrate intake, the liver converts fatty acids into ketone bodies.
These molecules replace glucose as an energy source for the brain, muscles, and vital organs.
Studies have shown that ketosis can improve brain energy efficiency, reduce neuroinflammation, and even have protective effects against neurodegenerative diseases such as Alzheimer’s and Parkinson’s (Newman & Verdin, Cell Metabolism, 2017).
What Science Is Still Investigating
Although the results are promising, most long-term studies are still limited. The scientific community is seeking to understand whether the positive metabolic effects are sustainable and safe after years of adherence.
There are also investigations into the impact of ketosis on longevity, gut microbiota, and athletic performance.
Proven Benefits and Indications
Despite being widely known for weight loss, the ketogenic diet has clinical indications and benefits investigated by science:
Refractory Epilepsy: The KD is historically a well-established and effective therapeutic intervention for seizure control in patients, especially children, with drug-resistant epilepsy. The exact mechanism is still under investigation, but the modulation of neurotransmitters and the effect of ketone bodies on the nervous system are suggested factors.
Weight Loss and Metabolic Syndrome: Short- and medium-term studies (up to 12 months) show that the KD can be effective in reducing weight and fat mass, as well as promoting improvements in metabolic parameters such as blood glucose, insulin sensitivity, and levels of triglycerides and HDL-C (“good” cholesterol) in patients with obesity and type 2 Diabetes Mellitus.
Satiety Factor: The high intake of fats and proteins contributes to increased satiety, which can lead to a spontaneous reduction in total caloric intake.
Research in Other Pathologies: There is growing interest in the use of the KD as an adjuvant therapy for cancer (due to the possible non-preference of tumor cells for ketone bodies) and neurodegenerative diseases (such as Alzheimer’s and Parkinson’s), although these studies are still in their initial stages and require more robust long-term evidence.
Conclusion: A Therapeutic Tool, Not a Universal Lifestyle
The ketogenic diet is, in fact, a powerful nutritional intervention with a strong scientific basis, especially proven in the treatment of epilepsy and with promise in the management of metabolic conditions. However, it should not be adopted indiscriminately. The success and safety of the diet depend on a rigorous and individualized meal plan that ensures adequate nutrient intake and monitoring of metabolic risks. Monitoring by a healthcare professional, such as a nutritionist or doctor, is essential to maximize the benefits and mitigate potential short- and long-term risks.