'Abdu'l-Baha says:-- Fasting is a symbol.

Fasting signifies abstinence from lust.
Physical fasting is a symbol of that abstinence, and is a reminder; that is, just as a person abstains from physical appetites, he is to abstain from self-appetites and self-desires.
But mere abstention from food has no effect on the spirit.

It is only a symbol, a reminder.

Otherwise it is of no importance.
Fasting for this purpose does not mean entire abstinence from food.

The golden rule as to food is, do not take too much or too little.