The small print of the keto diet, a fashion for slimming eating fat

Lose 12 kilos in a month without the smell of cauliflower flying over the kitchen for a single day. It is the dream of most people who are on a diet, and an experience that one can aspire to after seeing the stars of the show as Halle Berry, Jennifer Lopez, Kim Kardashian and Adriana Lima tell the wonders of the keto diet over the internet. The digital world's response to its recommendations has been overwhelming: it was the system that added more Google searches of 2018. And surely not only by the influence of singers and actresses, but also because it should be well informed if one tries to try.

the keto diet it disproportions the calories in such a way that fatty foods are predominant, with between 60% and 80% of the total intake. Then there are proteins (between 20% and 25%) and carbohydrates (5% to 10%), lists Juana María González Prada, dietitian-nutritionist and technical director of Alimmenta. But it's not worth any kind of fat. No bacon or bacon, "Ideally, the profile is healthy, preferably from fish and foods of vegetable origin (such as olive oil, seeds, nuts and avocado). A high intake of meat derivatives increases cardiovascular risk and cancer due to its content of saturated fats, cholesterol and sodium, explains González Prada.

The "magic" slimming of the Ketosis

The consequence of this distribution of nutrients is that the glycogen deposits, a molecule that is our main source of energy, remain virtually empty and the organism is forced to look for an alternative fuel. Then there is ketosis, which is a state in which the body uses fat — of worse quality and less efficient, so you have to burn more quantity — to achieve the energy that muscles and the brain need. The organism becomes an efficient lipid-burning machine, and the michelins disappear at full speed. This process inspires the name of the diet; The term keto is, precisely, a diminutive of ketogenic, which means "ketogenic" in English.

So far the dazzling headlines. Now, the small print. By minimizing the consumption of carbohydrates, one of the main macronutrients, It is also limited the intake of vitamins, minerals and fiber. And the intake of nutrients such as calcium, vitamin D, selenium, magnesium, zinc and phosphorus is compromised. It is a consequence that should be taken into account, since nutrients fulfil functions such as maintaining healthy muscles, ensuring adequate hormonal secretion, storing the health of the immune system and the heart, and maintaining the proper functioning of the Kidneys.

"The short-term symptoms of ketosis include constipation, headache, halitosis, muscle cramps, diarrhea, general weakness, and skin rashes. In the long term, health problems such as hepatic steatosis (better known as fatty liver disease), hypoproteinemia (decreased protein concentration), the appearance of stones in the kidneys, and deficiencies in vitamins and Minerals, "indicates the expert. Hence, many ketogenic diet-based programs include vitamin and mineral supplements to avoid unwanted consequences.

In addition, once the one who follows the diet has been made a figurine and decides to leave it usually appears the dreaded rebound effect. "weight is only maintained if there is a change in nutritional habits that can be maintained in time. If not, sooner or later he recovers, "says González Prada. And, although the keto diet is one of the fastest ways to lose weight, it is possible to achieve the same goal with some more time and achieve better results.

According to a meta-analysis that studied how the weight loss of subjects subjected to a diet low in carbohydrate compared to those of a diet low in fat, those of the ketogenic had lost of half 3.3 kilos more than their colleagues at the six months. But the differences were not very noticeable after a year. Instead, people who followed a low-fat diet had improved their cholesterol levels past that time.

Insufficient scientific literature not to think twice

The endocrine of the Mayo clinic Russell Wilder became one of the pioneers of the ketogenic diet when, at the beginning of the 1920s, he began using it to emulate the benefits of fasting in epilepsy patients. "The change arrives in the Fifties, with the publication of an article in the medical journal New England Journal of Medicine on the effects of this diet in obese patients and when, in 1972, Dr. Robert Atkins retakes The concept in his famous diet" , says Sonia Peinado, nutritionist at the European Medical Institute of Obesity. The rest is already history of one of the most famous and controversial regimes of the last half-century, the Atkins diet. The UK government came to order to investigate it in 2004, as part of an initiative to understand the increase in obesity in the country.

Recent studies aim to endorse the keto diet with new benefits for the organism. For example, reducing glucose in blood circulation improves insulin sensitivity and blood pressure. However, "there is no scientific evidence after a year," González Prada sentences. Others attribute an improvement in the symptomatology of Alzheimer's disease, but the expert considers that there is not enough data to support this thesis, nor those that argue that could be beneficial for some types of cancer. The same goes for those that attribute the power to stimulate the expression of anti-inflammatory and antioxidant genes to ketones, the chemical compounds that occur when the body burns fat. The latter allegedly would confer anti-ageing properties on the Keto diet.

"They are promises made from the study of laboratory animals, without scientific evidence in humans. What we do know, however, is that cetonemia (the increase of ketones in blood) during pregnancy has been associated with decreased IQ scores in children, "says González Prada.

And why do athletes resort to ketosis?

Apart from the controversy about its utility to lose weight, this diet finds shelter among some athletes. Since glycogen deposits are very limited, there are coaches who suggest getting the body to pull fat. It is an idea that circulates especially in resistance sports and in tests like the marathon, to avoid the gastrointestinal discomforts that can carry the gels.

"In terms of sports performance, a low-hydrate diet would not be my first choice if what the athlete is looking for is a good result in competition. The fat is worse fuel and does not allow to optimize the performance. In addition, the decrease in glycogen deposits is related to fatigue during exercise, "replies Marcos Rueda Córdoba, dietitian-nutritionist specializing in sports nutrition in Realfooding.

Another thing is to use it as a tool during the months of preparation of the test to teach the body to carburete with fats, which in the nutritionist jargon is known as seeking metabolic flexibility. "In certain training protocols, glycogen availability is reduced to increase fat oxidation as an energy source. But it is a double-edged sword: If you train a lot or always with low availability of glycogen, looking for these adaptations at metabolic level, perhaps not reach the same intensity or duration that would be achieved with the deposits of this main substrate Full. And this prevents other adaptations necessary to choose to win (to run faster or more kilometers). "

So, fat or glycogen? The most common solution is what Rueda Córdoba calls "nutritional periodization": "a part of the season is trained in low availability of carbohydrates. As we approach the competition, just the opposite: fill the glycogen deposits to the maximum to compete at the highest level, "concludes the expert.

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