The ketogenic diet (or in short – “keto”) has been considered one of the most popular methods in the world for weight loss in the past decade, but it was not created as a trendy diet at all, but as a medical treatment.
Originally, at the beginning of the 20th century, this method was developed as a treatment for children with epilepsy. It was found that when the body produces energy from fat instead of sugar, there is a significant decrease in the frequency of seizures.
Over the years, researchers noticed that in adults as well, the same diet rich in fat and very low in carbohydrates led to improvements in metabolic markers such as blood sugar, cholesterol, and triglyceride levels, and even helped some patients with diabetes reduce or stop medication.
How does it work?
The principle is simple but very extreme: The body enters a state called “ketosis” – a condition in which carbohydrate stores are almost depleted, and the body is forced to produce energy from the breakdown of fats. In this process, the body produces “ketone bodies,” which are a type of alternative fuel for the brain and muscles. The result is a different sense of energy, a decrease in appetite, and sometimes even rapid weight loss.
A classic ketogenic menu includes about 70%-80% fat (such as avocado, olive oil, nuts, butter, and fatty fish), about 15%-20% protein (meat, chicken, fish, eggs, high-fat cheeses), and less than 5%-10% carbohydrates – usually no more than 30–50 grams per day.
That means no bread, no pasta, no rice, no legumes, and most fruits – and only a few non-starchy vegetables like cucumber, zucchini, lettuce, and broccoli.
Basically, even “regular” dairy products are forbidden, such as yogurt, cottage cheese, or milk itself.
Despite the extreme menu, many people report a very good feeling of satiety, less craving for sweets, and weight loss even without strict calorie counting.
How do you lose weight even without counting calories?
There are several mechanisms working together:
The first is removing carbohydrates from the menu. Most of our excess calories come from processed carbohydrates: Bread, cookies, snacks. When these disappear, calorie intake drops almost automatically.
Another factor is the effect of protein on satiety. Proteins break down in the body into compounds that trigger feelings of fullness in the brain. The result: Less hunger, fewer snacks.
A third factor – higher calorie burning. Digesting proteins requires more energy compared to carbohydrates, so the body “burns” more even at rest.
In addition to all this, there is something else that directly affects but is not really related to body fat reduction – fluid loss: In the first weeks, there is a rapid weight drop mainly due to fluid loss, because carbohydrates “hold” water in the cells.
What does science say?
Various studies conducted in recent years have found that the ketogenic diet can be effective – but not always in the long term.
1. For example, a large study published in the New England Journal of Medicine followed hundreds of participants for a year and found that those who adhered to a very low-carbohydrate diet lost weight faster in the first few months, but after a year the differences almost disappeared, mainly because most participants could not continue with the strict menu.
2. In another study published in Diabetes Therapy, type 2 diabetes patients who stuck to a ketogenic diet for an entire year showed an average weight loss of 12 kg, improved blood sugar levels, and 60% of them managed to stop or reduce diabetes medication.
3. In contrast to the success studies, a study conducted at Harvard University found that in some participants there was an increase in LDL cholesterol (“bad cholesterol”) after a few months, mainly when the menu included large amounts of saturated fat from meats and high-fat cheeses.
4. A review published in Frontiers in Nutrition also emphasized that while the keto diet may be effective in the short term for weight loss and improving sugar balance, it may harm gut microbiome balance and cause constipation, fiber deficiency, and B vitamin deficiencies.
In other words – there are studies for and against it. The method works as long as you stick with it, but the difficulty of maintaining such an extreme diet causes many to gradually abandon it.
Even among those who continued long-term, results varied greatly – some lost 20 kg and felt great, while others reported fatigue, irritability, and cognitive decline, especially in the initial period.
What are the risks?
Like any extreme diet, the ketogenic diet is not suitable for everyone.
• It can be nutritionally unbalanced if not planned properly and may cause deficiencies in vitamins, minerals, and fiber.
• It is not recommended for people with kidney disease, diabetics taking insulin, or pregnant women.
• And also – not everyone can give up fruits, bread, or milk in their coffee.
Some people also report side effects in the first weeks, such as fatigue, headaches, constipation, or a “keto smell” in the nose and mouth – a result of ketone bodies in the blood. Usually, these are temporary effects, but they may make it difficult to persist.
The ketogenic diet may be suitable for those who have trouble controlling hunger, those who suffer from insulin resistance, and those who prefer a fixed and clear menu without daily calorie counting.
But it is important to emphasize: You must exercise discretion and do it under professional supervision by a dietitian/doctor. Personal adaptation according to blood tests, medical condition, and personal preferences is much more important than “being perfectly keto.”
For Dr. Maya Rosman’s course: How to improve your health and how to lose weight in a sensible and logical way – click here.