Skip sugars and, in return, eat a lot of fat: this slimming method is currently making the buzz. Rightly or wrongly? Decryption.
The number one injunction of the keto diet may be surprising, and for good reason: it is to eliminate almost all consumption of sugars, while “a person eats on average between 200 and 400 g of carbohydrates per day. This serves as fuel for the brain, which consumes 140 g of glucose per day,” explains Dr. Jean-Michel Lecerf, head of the nutrition department at the Institut Pasteur in Lille.
Without this contribution, the body will have to look for energy elsewhere, and that is the goal. For a few hours, it will tap into the carbohydrate stores located in the liver and muscles. “Then, for a few days, it will recover the amino acids present in the muscles and send them to the liver so that it makes sugar, continues the doctor. This process is bad for your health, as it leads to muscle loss. »
Guaranteed grease melting
However, in a third step, a new system is set up: the body’s fats are directly used to produce ketone bodies: substances that will nourish the brain. We talk about a ketogenic diet. The state of ketosis – detectable with urine test strips – is then reached and allows weight loss, since fat has become fuel. But, in order for this new balance to be maintained, a strict diet based on fat is essential. On a daily basis, you must compose your menus of 80% fat, no more than 5% carbohydrates, and limit protein to 15%, to prevent the body from transforming them into sugars. The effects on weight are rapid and bluffing with often 1 kilo or more lost in the first week when a standard diet makes you lose 2 to 3 kilos on average in a month. Another advantage: the feeling of satiety linked both to the state of ketosis, but also to a more satiating fatty diet.
Lack of fiber… and back to square one
On a daily basis, relying solely on low-carbohydrate vegetables – such as cruciferous vegetables (cauliflower, broccoli) and leafy vegetables (lettuce, endive, spinach) – and zapping fruits can lead to vitamin deficiencies. In addition, “eating on the model of the keto diet means no longer filling up on fiber, while the microbiota, essential to our good health and which participates in our immune system, absolutely needs it,” points out Dr. Lecerf. Some people may also suffer from constipation, due to this lack of fiber related to the low ratio of plants. To all this is added the overconsumption of fat, which must be done with caution. Saturated fats (red meat, cheese, butter) are indeed associated with hypercholesterolemia and cardiovascular diseases; it will therefore be necessary to take care to favor rather the “good fats”, of vegetable origin. In the end, this diet is a little varied and repetitive, risking in the long run to destroy any motivation. And all that… to go back to square one, since, according to Dr. Lecerf, “as after all restrictive diets, there will always be a weight gain”. “The keto diet is difficult to follow in the long term,” confirms dietician Charlotte Debeugny. In order to succeed in slimming sustainably, I advise you to follow it for a month, then to follow the following month on a “low carb” diet, low in sugars but less restrictive. From the third month, it is better to switch to the Mediterranean diet, very good for line and health!»
Promises to be confirmed
Despite its disadvantages, the ketogenic diet seduces, because it breaks the principle of traditional slimming diets, which consists in banning fats. Frankly, who has never dreamed of losing weight while eating avocado or cheese? We are witnessing a real “ketomania”, many “special keto” books have emerged in recent months. Some authors boast benefits that go far beyond weight loss and say that diets could also reduce fatigue related to autoimmune diseases, reduce chronic migraines, improve the daily lives of people with Alzheimer’s or help fight cancer. Properties “that have not yet been attested by scientific research on humans on a large scale and in the long term,” says Dr. Lecerf. Most of the studies have indeed been carried out on animals. However, two promising avenues are attracting attention: the effect of the keto diet on the regression of certain cancerous brain tumors and, in the treatment of diabetes, the conclusions of work according to which this diet could bring improvements for adults, especially in weight loss. “But this hyperlipidemic diet increases cardiovascular risks, the leading cause of death for people with diabetes, so it is still unknown whether, in the long term, the benefit is greater than the risk,” warns the doctor.
A solution against epilepsy
What few people know is that the keto diet is, originally, a medical diet. As early as the 20s and 30s, doctors noticed its positive effect on children with epilepsy. Since then, ketone bodies absorbed by the brain have been shown to alter neuronal activity. “The only accepted and verified indication of this diet is, therefore, treatment-resistant epilepsy, especially in children,” notes Dr. Lecerf. We then use this diet in a very supervised way and, in general, after a certain time, we can stop it, because the seizures stop. »
What’s on the menu?
Foods to favor Oilseeds, avocado, cheese, fresh cream, cream, coconut and olive oil, cabbage, cucumber, asparagus, green beans, endive, spinach, green pepper, green salad, tomato, red fruits, rhubarb, meat, fish, eggs. Foods to forget Bread, potatoes, pasta, rice, cereals, sugar and sweet products (sweets, honey, cakes …), sweet vegetables (beetroot, carrot …), most fruits, legumes, milk. The typical day An avocado or a bowl of Greek yogurt and nuts at breakfast. A fillet of fish or chicken with lots of spinach at noon. Oil at will! Nuts or seeds as a snack. Cream mushrooms with broccoli and a piece of cheese in the evening.