In recent years, the ketogenic diet has risen to stardom, promising a radical transformation: losing weight while enjoying high-fat foods. Specifically, this nutritional regimen asks you to forget bread, rice and potatoes, among other foods, and instead invites you to indulge in cheeses, avocados, nuts and healthy oils. Sounds tempting, right?
We are talking about an almost surreal proposal: eat more fat to lose fat. Its defenders praise it as a true metabolic revolution, a trick that hack your body to burn fat at full speed. But, Is it really a game changer, or are we betting blindly?
The reality is that the ketogenic diet has both devoted followers and fierce detractors. For some, it has been the magic key that allowed them to lose weight, improve their energy and mental clarity. For others, it represents a path fraught with danger: dizziness, fatigue, bad breath and even more serious health risks, both physical and psychological, if taken to the extreme.
We tell you how this diet really works, what its promises are and, more importantly, what the risks that could accompany it are. Because behind every nutritional trend there is always more than what is seen on the surface, and the ketogenic diet is no exception.
What is a ketogenic diet: main objective and types
Elena Rivero, nutritionist at the Sarai Alonso Nutritionists clinic, specialist in advanced clinical nutrition and expert in eating disorders (ED), women’s hormonal health and obesity, explains that the ketogenic diet, also known as keto dietIt is a type of diet low in carbohydrates and high in fat which aims to induce the body into a state of ketosis. “The purpose of this type of diet is to imitate a state of fasting, without obtaining the negative consequences of starvation,” says the nutritionist.
In this way, both the ketogenic diet and low-carbohydrate diets share the goal of reducing carbohydrate intake. The main difference is that the ketogenic diet is premised on induce the state of ketosis and, to do this, the reduction of carbohydrates must be extremely low and the consumption of fats increases considerably. In contrast, in low carbohydrate diets, It is not necessarily intended to enter a state of ketosis.
Elena Rivero distinguishes five different types of ketogenic diet:
- Standard ketogenic diet (SCD): It is the most common type of ketogenic diet and, at the same time, stricter. The objective of this regimen is to maintain the state of ketosis permanently in the body. In this eating plan, the intake of carbohydrates at 5-10% of the total caloric value (TCV) and abounds in fat intake, providing 70-80% of the VCT.
- Cyclic Ketogenic Diet (CCD): this alternate diet 5 days of ketogenic diet and 2 days with a higher carbohydrate intake. This ketogenic diet is usually used in athletes with the aim of replenishing muscle glycogen without leaving ketosis in the long term.
- Targeted Ketogenic Diet (DCD): It’s actually the standard ketogenic diet but introduce carbohydrate intake before and after sports practice to improve performance.
- High protein ketogenic diet: It is a variant of the standard ketogenic diet. In this type of diet the carbohydrate intake remains 5-10% of the VCT but is reduce fat to 60%, to be able to introduce more protein into the diet: This type of plan is designed to improve diet adherence or adapt to the needs of an athlete.
- Therapeutic type ketogenic diet: It is a diet that is only used in clinical situations with the aim of improving the treatment of certain pathologies, such as, for example, refractory epilepsy in children or neurological diseases such as Parkinson’s. They tend to be more strict and are supervised by the entire medical team.
Health benefits associated with the ketogenic diet
The ketogenic diet may have health benefits when an extreme state of ketosis is not reached. Among the benefits, Elena Rivero highlights:
- A decreased circulating glucose, reduced fasting insulin levels, and reduced insulin resistance. Therefore, it could be interesting for patients with diabetes mellitus.
- The ketogenic diet could improve metabolic profile in healthy people. In a period of 6-12 months you can observe transient decreases in blood pressure, triglycerides, and an increase in HDL cholesterol. But as a consequence of the increase in fat intake, LDL cholesterol also increases. Therefore, it is a diet that may not be suitable for everyone, and medical advice should be sought before carrying it out.
- Reduction of oxidative stress and inflammation markers.
- Can reduce migraine attacks and symptoms of some neurological conditions such as epilepsy, Alzheimer’s and Parkinson’s.
- The ketogenic diet could help obesity management. Although there is not enough scientific evidence for the ketogenic diet in weight loss, there is evidence that the ketogenic diet can help reduce appetite due to increased fat and protein in the diet. In addition, the state of ketosis has an effect on the secretion of hormones related to the regulation of appetite. However, according to the nutritionist, there is a lack of exhaustive studies that guarantee the safety of use in weight loss. Also in the short term, you can lose weight quickly but due to the loss of water in the body, not due to the loss of fat.
Adverse effects of the ketogenic diet: everything you need to know
Although the ketogenic diet has gained popularity as an effective weight loss tool, is not free of side effects. Elena Rivero explains that during the transition to this regime, the body undergoes a process known as ketoadaptationwhich can bring with it the following complications:
- “Ketogenic flu”: During the change of energy source, when going from carbohydrates to fats, it is common for what is known as “keto flu” to occur. “It is a phenomenon that causes symptoms such as fatigue, headache and lethargy. Although these effects tend to improve over time, as the body adapts to using fat as its main source of energy, it is something that many find difficult to manage at first,” explains Rivero.
- Gastrointestinal discomfort: Another common complaint among those starting the ketogenic diet is digestive problems, such as constipation or nausea. “This may be due to the change in fiber intake and the alteration in metabolism, which takes time to adjust,” adds the expert.
- Nutritional deficiencies: The ketogenic diet can also lead to imbalances in the body. “Hydroelectrolyte alterations, dehydration and hypovitaminosis These are some of the risks associated with poor planning of this diet. It is crucial to pay attention to mineral and vitamin levels, since restricting certain food groups can cause significant deficiencies,” warns Rivero.
In addition, according to the nutritionist, those who follow this regimen may also face an increased likelihood of developing kidney stones, an increase in blood uric acid levels and an increased risk of osteoporosis in the long term.
The process of adaptation to ketosis: what happens in the body?
Elena Rivero explains the physiological changes that the body goes through when entering a state of ketosis. Under normal conditions, the body obtains its energy from carbohydrates, transforming them into glucose. However, when carbohydrate intake decreases dramatically, the body must look for an alternative energy source.
“The key is insulin”sentence. “By reducing carbohydrate consumption, blood glucose levels drop significantly. Normally, glucose is the body’s preferred source of energy, and insulin is responsible for transporting that glucose to the cells for use,” details Rivero. . “When there is less glucose available, insulin levels also decrease. This is key, because low insulin makes it easier for the body to access fat reserves to produce energy,” he adds.
At first, the body resorts to glycogen reserves stored in the liver and musclesbut these are depleted after about three or four days of low carbohydrate intake. “Once glycogen reserves are depleted, the body needs a new source of energy. That’s when body fat comes into play,” says the specialist in women’s hormonal health.
Later, when the body begins to break down fat, the free fatty acids are transported to the liver, where they are transformed into ketones. These ketones act as an alternative source of energy for the brain, muscles, and other organs. “The state of nutritional ketosis turns the body into a kind of ‘fat-burning machine’, which mainly uses ketones and fatty acids instead of glucose to function,” explains the specialist.
The transition into ketosis can take several days, and during this period it is common to experience symptoms such as fatigue, dizziness, and headaches, collectively known as the “keto flu.” These effects usually disappear once the body fully adapts to the new energy source.
Is the ketogenic diet for everyone?
Despite its growing popularity, “it is not recommended that anyone immerse themselves in a ketogenic diet, as it can have adverse effects for certain groups” warn specialists.
For example, Children and pregnant women should avoid this type of regimen. “At these stages of life, nutritional needs are different and more complex. Subjecting the body to such a severe restriction of carbohydrates can have negative consequences for development and general health,” says nutritionist Sarai Alonso on her blog.
These groups are also joined people with kidney pathologies and those who present imbalances in metabolic homeostasis. For them, ketosis could aggravate certain conditions or cause additional complications. Furthermore, Alonso emphasizes that for people with eating disorders (ED)the ketogenic diet is “completely inadvisable.” “It is a type of diet that restricts foods and subjects the person to very strict dietary control, something that can trigger or aggravate mental health problems in those who suffer from EDs“he adds.
For all this, the expert emphasizes the importance of medical supervision. “It is essential that anyone interested in following a ketogenic diet do so under the supervision of a health professional. Ideally, it should be guided by a specialized dietitian-nutritionist, who can adapt the plan to individual needs and monitor the patient’s health throughout the process,” concludes Alonso.