Oriol Roda and Néstor Sánchez, authors of 'Keto Health', explain what ketosis is. Ketosis is the physiological state we enter when our body needs to use its fat reserves.

"Our body is designed for a world of scarcity where accumulating fat was the best strategy to survive," they maintain. They explain in a simple way that we eat more than we need and the failure of the low-calorie diet. The ketogenic diet is another strategy, not the only way to enter ketosis.