The ketogenic diet is a diet that drastically reduces carbohydrates, increasing proteins and especially fats. The main purpose of this imbalance in the proportions of macronutrients in the diet is to force the body to use fats as a source of energy.
This helps to consume fat more efficiently, resulting in weight loss that does not affect lean mass. 
In the presence of carbohydrates, in fact, all cells do not use energy to carry out their activities. But if these are reduced to a sufficiently low level they begin to use fats, all except nerve cells that do not have the ability to do so. A process called ketosis then begins , because it leads to the formation of molecules called ketone bodies, this time usable by the brain. Generally, ketosis is achieved after a couple of days with a daily amount of carbohydrates of about 20-50 grams , but these quantities can vary on an individual basis.
Erythritol or erythrol as many call it is the ideal product for this type of diet because even if you have a drastic lack of carbohydrates and sugars you can still continue to enjoy your favorite sweets or dishes, since erythritol works as a substitute for sugar and has a calorie content equal to exactly 0, does not cause glycemic peaks and therefore does not interrupt the state of ketosis when taken.
Yes to sweet drinks and foods, not to excess carbohydrates! 