Low caloric diets mainly consider caloric intake and, most of the time, disregard the number of macronutrients like carbohydrates, proteins and fats, not to mention vitamins, minerals and antioxidants.
Fasting is an entirely different thing.
Fasting can be done by including a nutritious and balanced diet.
Both diets are not to be used without professional guidance.
For more information, please read my books available on this website.
I know those terms seem almost the same, but they are very different.