The diet is designed to lose up to 12 kilos in a month, but its extreme nature can produce side effects.
Losing 12 kilos in a month without the smell of cauliflower overflow the kitchen a single day. It is the dream of most people who go on a diet, and an experience that one can aspire after seeing stars of the show like Halle Berry, Jennifer Lopez, Kim Kardashian, and Adriana Lima tell the wonders of the diet keto by the Internet. The response of the digital world to its recommendations has been overwhelming: it was the regime that added more Google searches in 2018. And certainly not only because of the influence of singers and actresses but also because it is advisable to be well informed if one tries to prove it.
The keto diet distributes 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 (from 5% to 10%), says Juana María González Prada, dietitian-nutritionist and technical director of Alimmenta. But it is not worth any type of fat. No bacon or rashers, “the ideal is that the profile is healthy, preferably from fish and foods of vegetable origin (such as olive oil, seeds, nuts, and avocados). Elevated intake of meat derivatives increases the cardiovascular risk and of suffering from cancer due to its content in saturated fats, cholesterol and sodium “, explains González Prada.
The “magic” slimming of ketosis
The consequence of this distribution of nutrients is that the glycogen deposits, a molecule that is our main source of energy, are practically empty and the body is forced to look for alternative fuel. Then ketosis is produced, which is a state in which the body uses fat – of lower quality and less efficient, so you have to burn more – to achieve the energy needed by the muscles and the brain. The organism becomes an efficient machine to burn lipids, and the love handles 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 fine print. By minimizing the consumption of carbohydrates, one of the main macronutrients, the intake of vitamins, minerals, and fiber is also limited. 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 the nutrients perform functions such as maintaining healthy muscles, ensuring adequate hormonal secretion, maintaining the health of the immune system and the heart, and maintaining the proper functioning of the kidneys.
“Short-term symptoms of ketosis include constipation, headache, halitosis, muscle cramps, diarrhea, general weakness and skin rashes, and long-term health problems such as hepatic steatosis ( better known as fatty liver disease), hypoproteinemia (decreased protein concentration), the appearance of kidney stones and deficiencies of vitamins and minerals, “says the expert. Hence, many programs based on the ketogenic diet include vitamin and mineral supplements, to avoid unwanted consequences.
In addition, once someone who follows the diet has been made a figurine and decides to leave it usually appears the dreaded rebound effect. “The weight is only maintained if there is a change in nutritional habits that can be maintained over time, if not, sooner or later it will recover,” 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 a little more time and get better results.
According to a meta-analysis that studied how the weight loss of subjects subjected to a low-carbohydrate diet evolves compared to those of a low-fat diet, those of the ketogenic diet had lost an average of 3.3 kilos more than their colleagues at six months. But the differences were not appreciable after a year. In contrast, people who followed a low-fat diet had improved their cholesterol levels after that time.
Insufficient scientific literature not to think twice
The Mayo Clinic’s endocrinologist Russell Wilder became one of the pioneers of the ketogenic diet when, in the early 1920s, he began using it to emulate the benefits of fasting in epileptic patients. “The change comes in the fifties, with the publication of an article in the New England Journal of Medicine about the effects of this diet in obese patients and when, in 1972, Dr. Robert Atkins takes up the concept in his famous diet “, points out Sonia Peinado, nutritionist of the European Medical Institute of Obesity. The rest is already the history of one of the most famous and controversial regimes of the last half-century, the Atkins diet. The Government of the United Kingdom 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 body. For example, reducing glucose in the bloodstream improves insulin sensitivity and blood pressure. However, “there is no scientific evidence after one year”, González Prada says. Others attribute an improvement in the symptoms of Alzheimer’s disease, but the expert believes that there is not enough data to support this thesis, nor those that maintain that it could be beneficial for some types of cancer. The same goes for those who attribute the power to stimulate the expression of anti-inflammatory and antioxidant genes to ketones, the chemical compounds that are produced when the body burns fat. The latter supposedly confer anti-aging properties to the keto diet.
“They are promises made from the study of laboratory animals, without scientific evidence in humans, but what we do know, on the other hand, is that ketonemia (the increase in blood ketones) during pregnancy has been associated with decreased scores of the intelligence quotient in children “, indicates González Prada.
And why do athletes resort to ketosis?
Apart from the controversy about its usefulness to lose weight, this diet finds refuge among some athletes. Since glycogen stores are very limited, there are coaches who suggest getting the body used to pulling fats. It is an idea that circulates mainly in endurance sports and in tests like the marathon, to avoid the gastrointestinal discomfort that gels can cause.
“In terms of sports performance, a low-carbohydrate diet would not be my first choice if what the athlete is looking for is a good result in competition, grease is worse fuel and does not optimize performance. Glycogen is related to fatigue during exercise, “says Marcos Rueda Córdoba, dietitian-nutritionist specializing in sports nutrition at Realfooding.
Another thing is to use it as a tool during the months of preparation of the test to teach the body to the carburetor with fat, what in nutritionist jargon is known as seeking metabolic flexibility. “In certain training protocols, the availability of glycogen is reduced to increase the oxidation of fats 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 those adaptations at the metabolic level, perhaps it will 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 win (achieving faster or more kilometers). ”
So, fat or glycogen? The most common solution is what Rueda Córdoba calls “nutritional periodization”: “Part of the season is trained in low carbohydrate availability, as we approach the competition, just the opposite: fill the glycogen deposits to the maximum to compete at the highest level “, concludes the expert.