Cereal-based foods (bread, pasta, rice), potatoes, prepared meals, sweets, cakes, and milk (rich in lactose, which is a carbohydrate) should be avoided.
Certain fruits and vegetables, too rich in carbohydrates (a banana provides about 30 grams of carbohydrates out of the 50 required), are also to be avoided, as well as legumes.
How does it work?
To function, the body has three types of food fuels: carbohydrates, fats, and proteins. When carbohydrates are very low - as is the case with the ketogenic diet - the liver begins to manufacture ketone bodies from dietary fat or fat stores in the body.
The body is said to be in “ketosis”: it turns into a fat “burning” machine. Ketone bodies, therefore, become the main source of energy for most of our cells.
This change occurs on average between two and four days after the adoption of the regime.
Does the ketogenic diet help you lose weight?
"A drastic diet of this type is certainly weight loss," says Professor Cynober. “The individual can lose several pounds in a month. But the problem with these extreme diets is that there is a rebound effect."The problem with these extreme diets is that there is a rebound effect. Often people regain more weight than they initially lost. - Professor Luc Cynober"
“Studies have shown that low-sugar diets lead to faster weight loss than low-fat diets.
But in the long term, the weight curves converge,” says Dr. François Jornayvaz, head of the diabetology unit at the University Hospitals of Geneva and author of several scientific articles on the ketogenic diet.
According to the doctor, this diet – where carbohydrates are virtually eliminated – must be distinguished from low-sugar diets.
"We have reason to think that moderately low carbohydrate diets, which do not exceed 130 grams of sugar per day, could be beneficial, especially for diabetic patients," he says.
But you have to be extremely careful about the type of fats consumed and favor those of vegetable rather than animal origin, otherwise, there is a risk of developing fatty liver (hepatic steatosis) and hypercholesterolemia, with harmful effects in the long term.
For the moment, even if the promises of the ketogenic diet extend (weight loss, but also cancer, Alzheimer's disease, etc.), it should be remembered that its effectiveness has only been scientifically proven in epilepsy.
Are there any side effects?
In the short term, switching from a conventional diet to a ketogenic diet can lead to nausea, constipation, fatigue, headaches, cramps, bad breath...
So many inconveniences are mainly related to dehydration.
"With this diet, the body is forced to use its glucose reserves,"
explains Professor Luc Cynober. “
But in muscle, glucose is stored with water. Its use, therefore, leads to the elimination of water which contributes to weight loss but also to dehydration”.
This diet, which involves a decrease in the consumption of fruits and vegetables, can also lead to deficiencies.
"There may be a deficit of vitamins, minerals and fiber,"
says Professor Cynober. Hence the need to take advice from a dietitian or nutritionist before embarking on such an undertaking.
In the long term, the consequences are poorly known. Most of the scientific work done so far involves a small number of participants and/or does not include a control group for comparison.
'The strongest data we have comes from children with epilepsy,'
says Dr. Jornayvaz. “They show that there is, in the long term, a risk of developing kidney stones, osteoporosis, and a growth disorder”.
"Man is programmed for balanced and omnivorous diets. Needless to say, stuffing the body with fat by crowding out carbohydrates is probably not good for your health." - Professor Luc Cynober
In a report on weight-loss diets published in 2010, the National Food Safety Agency (ANSES) recalled that "the search for weight loss without formal medical indication involves risks, in particular when recourse is had to practices unbalanced and poorly diversified diets”. In addition, the Agency stressed that "nothing can replace, in terms of health, a balanced, diversified diet, ensuring that daily energy intake does not exceed requirements."
